Chapter 5 Conjunctiva

INTRODUCTION 132

Anatomy 132

Histology 132

Clinical features of conjunctival inflammation 132

BACTERIAL CONJUNCTIVITIS 135

Acute bacterial conjunctivitis 135

Adult chlamydial conjunctivitis 137

Trachoma 139

Neonatal conjunctivitis 139

VIRAL CONJUNCTIVITIS 142

Adenoviral conjunctivitis 142

Molluscum contagiosum conjunctivitis 143

ALLERGIC CONJUNCTIVITIS 144

Acute allergic conjunctivitis 144

Seasonal and perennial allergic conjunctivitis 144

Vernal keratoconjunctivitis 145

Atopic keratoconjunctivitis 147

Treatment of VKC and AKC 150

Giant (mechanically-induced) papillary conjunctivitis 151

CONJUNCTIVITIS IN BLISTERING MUCOCUTANEOUS DISEASE 152

Mucous membrane pemphigoid 152

Stevens–Johnson syndrome/toxic epidermal necrolysis (Lyell syndrome) 154

MISCELLANEOUS CONJUNCTIVITIS 158

Superior limbic keratoconjunctivitis 158

Ligneous conjunctivitis 160

Parinaud oculoglandular syndrome 162

Factitious conjunctivitis 162

DEGENERATIONS 162

Pingueculum 162

Pterygium 163

Concretions 165

Conjunctivochalasis 165

Retention (epithelial inclusion) cyst 165

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Introduction

Anatomy

The conjunctiva is a transparent mucous membrane lining the inner surface of the eyelids and the surface of the globe as far as the limbus. It is richly vascular, supplied by the anterior ciliary and palpebral arteries. There is a dense lymphatic network, with drainage to the preauricular and submandibular nodes corresponding to that of the eyelids. It has a key protective role, mediating both passive and active immunity. Anatomically, it is subdivided into the following:

1 The palpebral conjunctiva starts at the mucocutaneous junction of the lid margins and is firmly attached to the posterior tarsal plates. The underlying tarsal blood vessels can be seen passing vertically from the lid margin and fornix.

2 The forniceal conjunctiva is loose and redundant and may be thrown into folds.

3 The bulbar conjunctiva covers the anterior sclera and is continuous with the corneal epithelium at the limbus. Radial ridges at the limbus form the palisades of Vogt. The stroma is loosely attached to the underlying Tenon capsule, except at the limbus, where the two layers fuse. A plica semilunaris (semilunar fold) is present nasally, medial to which lies a fleshy nodule (caruncle) consisting of modified cutaneous tissue containing hair follicles, accessory lacrimal glands, sweat glands and sebaceous glands.

Histology

1 The epithelium is non-keratinizing and around five cell layers deep (Fig. 5.1). Basal cuboidal cells evolve into flattened polyhedral cells before they are shed from the surface. Goblet cells are located within the epithelium and are densest inferonasally and in the fornices.

2 The stroma (substantia propria) consists of richly vascularized loose connective tissue. The adenoid superficial layer does not develop until about 3 months after birth, hence the inability of the newborn to produce a follicular conjunctival reaction. The deep fibrous layer merges with the tarsal plates. The accessory lacrimal glands of Krause and Wolfring are located deep within the stroma. Mucus from the goblet cells and secretions from the accessory lacrimal glands are essential components of the tear film.

3 Conjunctiva-associated lymphoid tissue (CALT) is critical in the initiation and regulation of ocular surface immune responses. It consists of lymphocytes within the epithelial layers, lymphatics and associated blood vessels, with a diffuse stromal component of lymphocytes and plasma cells, including follicular aggregates.

Fig. 5.1 Histology of the conjunctiva

(Courtesy of J Harry)

Clinical features of conjunctival inflammation

Symptoms

Non-specific symptoms include lacrimation, grittiness, stinging and burning. Itching is the hallmark of allergic disease, although it may also occur to a lesser extent in blepharitis and dry eye. Significant pain, photophobia or a marked foreign body sensation suggest corneal involvement.

Discharge

1 Watery discharge is composed of a serous exudate and tears and occurs in acute viral or acute allergic conjunctivitis.

2 Mucoid discharge is typical of chronic allergic conjunctivitis and dry eye.

3 Mucopurulent discharge typically occurs in chlamydial or acute bacterial infection (see Fig. 5.4C).

4 Moderately purulent discharge occurs in acute bacterial conjunctivitis.

5 Severe purulent discharge is typical of gonococcal infection (see Fig. 5.4D).

Conjunctival reaction

1 Hyperaemia (‘injection’) that is diffuse, beefy-red and more intense away from the limbus is typical of bacterial infection (Fig. 5.2A).

2 Haemorrhages (Fig. 5.2B) may occur with viral and occasionally bacterial conjunctivitis.

3 Chemosis (conjunctival oedema) may occur when severe inflammation produces a translucent swelling (Fig. 5.2C and see Fig. 5.11) which, if severe, may protrude through the closed lids. Acute chemosis usually indicates a hypersensitivity response whereas chronic oedema suggests orbital outflow constriction.

4 Membranes

a Pseudomembranes consist of coagulated exudate adherent to the inflamed conjunctival epithelium (Fig. 5.2D). They can be peeled easily leaving the underlying epithelium intact (see Fig. 5.23B).

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b True membranes involve the superficial layers of the conjunctival epithelium so that attempted removal leads to tearing.

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c Causes

• Severe adenoviral conjunctivitis.

• Gonococcal conjunctivitis.

• Ligneous conjunctivitis.

• Acute Stevens–Johnson syndrome.

• Bacterial infection (Streptococcus spp., Corynebacterium diphtheriae)

Fig. 5.2 Signs of conjunctival inflammation. (A) Injection; (B) haemorrhages; (C) chemosis; (D) pseudomembrane; (E) infiltration; (F) subconjunctival scarring

(Courtesy of P Saine – fig. A; S Tuft – fig. B; M Jager – fig. F)

The distinction between a true and a pseudomembrane is rarely clinically helpful and both can leave scarring following resolution.

5 Infiltration represents cellular recruitment to the site of chronic inflammation and typically accompanies a papillary response. It is recognized by loss of detail of the normal tarsal conjunctival vessels, especially on the upper lid (Fig. 5.2E).

6 Subconjunctival scarring (Fig. 5.2F) may occur in trachoma and other types of cicatrizing conjunctivitis. Severe scarring is associated with loss of goblet cells and accessory lacrimal glands, and can lead to cicatricial entropion.

7 Follicles

a Signs. Multiple, discrete, slightly elevated lesions resembling translucent grains of rice, most prominent in the fornices (Fig. 5.3A). Blood vessels run around or across rather than within the lesions.

b Histology shows a subepithelial lymphoid germinal centre with central immature lymphocytes and mature cells peripherally (Fig. 5.3B).

c Causes include viral and chlamydial conjunctivitis, Parinaud oculoglandular syndrome and hypersensitivity to topical medications. Small follicles are a normal finding in childhood (folliculosis), as are follicles in the fornices and at the margin of the upper tarsal plate in adults.

8 Papillae can develop only in the palpebral conjunctiva and in the limbal bulbar conjunctiva where it is attached to the deeper fibrous layer.

a Signs

• In contrast to follicles, a vascular core is present.

• Micropapillae form a mosaic-like pattern of elevated red dots as a result of the central vascular channel (see Fig. 5.12A).

• Macropapillae (<1 mm – Fig. 5.3C) and giant papillae (>1 mm) develop with prolonged inflammation.

• Apical staining with fluorescein or the presence of mucus between giant papillae (see Fig. 5.12C) indicates active disease.

• Limbal papillae have a gelatinous appearance (see Fig. 5.13).

b Histology shows folds of hyperplastic conjunctival epithelium with a fibrovascular core and subepithelial stromal infiltration with inflammatory cells (Fig. 5.3D). Late changes include superficial stromal hyalinization, scarring, and the formation of crypts containing goblet cells.

c Causes include bacterial conjunctivitis, allergic conjunctivitis, chronic marginal blepharitis, contact lens wear, superior limbic keratoconjunctivitis and floppy eyelid syndrome.

Fig. 5.3 (A) Conjunctival follicles; (B) histology of a follicle shows two subepithelial germinal centres with immature lymphocytes centrally and mature cells peripherally; (C) conjunctival macropapillae; (D) histology of a papilla shows folds of hyperplastic conjunctival epithelium with a fibrovascular core and subepithelial stromal infiltration with inflammatory cells

(Courtesy of S Tuft – figs A and C; J Harry – figs B and D)

Lymphadenopathy

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The most common cause of lymphadenopathy associated with conjunctivitis is viral infection. It may also occur in chlamydial and severe bacterial conjunctivitis (especially gonococcal), and Parinaud oculoglandular syndrome. The preauricular site is typically affected.

Bacterial conjunctivitis

Acute bacterial conjunctivitis

Acute bacterial conjunctivitis is a common and usually self-limiting condition caused by direct eye contact with infected secretions. The most common isolates are S. pneumoniae, S. aureus, H. influenzae and Moraxella catarrhalis. A minority of cases, usually severe, are caused by the sexually transmitted organism Neisseria gonorrhoeae, which can readily invade the intact corneal epithelium. Meningococcal (Neisseria meningitidis) conjunctivitis is rare, and usually affects children.

Diagnosis

1 Symptoms

• Acute onset of redness, grittiness, burning and discharge.

• Involvement is usually bilateral although one eye may become affected 1–2 days before the other.

• On waking, the eyelids are frequently stuck together and may be difficult to open.

• Systemic symptoms may occur in patients with severe conjunctivitis associated with gonococcus, meningococcus, Chlamydia and H. influenzae.

2 Signs are variable and depend on the severity of infection.

• Eyelid oedema and erythema may occur in severe infection, particularly gonococcal (Fig. 5.4A).

• Conjunctival injection as previously described (Fig. 5.4B and see Fig. 5.2A).

• The discharge can initially be watery, mimicking viral conjunctivitis, but rapidly becomes mucopurulent (Fig. 5.4C).

• Hyperacute purulent discharge may signify gonococcal or meningococcal conjunctivitis (Fig. 5.4D).

• Superficial corneal punctate epithelial erosions are common.

• Peripheral corneal ulceration may occur in gonococcal and meningococcal infection (Fig. 5.4E), and may rapidly progress to perforation.

• Lymphadenopathy is usually absent except in severe gonococcal and meningococcal infection.

3 Investigations are not performed routinely but may be indicated in the following situations:

• In severe cases, binocular conjunctival swabs and scrapings should be taken for urgent Gram staining, particularly to exclude gonococcal and meningococcal infection (Gram-negative kidney-shaped intracellular diplococci – Fig. 5.4F).

• Culture on enriched media such as chocolate agar or Thayer–Martin for N. gonorrhoeae.

• Polymerase chain reaction (PCR) may be required for less severe cases which fail to respond to treatment, particularly to rule out the possibility of chlamydial and viral infection.

Fig. 5.4 Bacterial conjunctivitis. (A) Eyelid oedema and erythema in severe infection; (B) diffuse conjunctival injection involving the tarsal and forniceal conjunctiva; (C) mucopurulent discharge; (D) profuse purulent discharge; (E) superior corneal ulceration; (F) Gram stain shows kidney-shaped diplococcic

(Courtesy of S Tuft – fig. E; S Lewellen – fig. F)

Treatment

About 60% of cases resolve within 5 days without treatment.

1 Topical antibiotics (q.i.d. for up to 1 week) are frequently administered to speed recovery and prevent re-infection and transmission. There is no evidence that any particular antibiotic is more effective. Ointments and gels provide a higher concentration for longer periods than drops but daytime use is limited because of blurred vision. The following antibiotics are available:

• Chloramphenicol, aminoglycosides (gentamicin and neomycin), quinolones (ciprofloxacin, ofloxacin, levofloxacin, lomefloxacin, gatifloxacin and moxifloxacin), polymyxin B, fusidic acid and bacitracin.

• Some practitioners believe that chloramphenicol should not be used for routine treatment because of a possible link with aplastic anaemia.

• Gonococcal and meningococcal conjunctivitis should be treated with a quinolone, gentamicin, chloramphenicol or bacitracin 1–2 hourly as well as systemic therapy (see below).

2 Systemic antibiotics are required in the following circumstances:

a Gonococcal infection is usually treated with a third-generation cephalosporin such as ceftriaxone; quinolones and some macrolides are alternatives. It is advisable to seek advice from a microbiologist and/or genitourinary specialist.

b H. influenzae infection, particularly in children, is treated with oral amoxicillin with clavulanic acid because there is a 25% risk of developing otitis and other systemic problems.

c Meningococcal conjunctivitis, also particularly in children, in whom early systemic prophylaxis may be life-saving as up to 30% develop invasive systemic disease. The advice of paediatric and infectious disease specialists should be sought but if in doubt treatment with intramuscular benzylpenicillin, ceftriaxone or cefotaxime, or oral ciprofloxacin should not be delayed.

d Preseptal or orbital cellulitis (see Ch. 3).

3 Topical steroids may reduce scarring in membranous and pseudomembranous conjunctivitis, although evidence for their use is unclear.

4 Irrigation to remove excessive discharge may be useful in hyperpurulent cases.

5 Contact lens wear should be discontinued until at least 48 hours after complete resolution of symptoms. Contact lenses should not be worn whilst topical antibiotic treatment continues.

6 Risk of transmission should be reduced by hand-washing and avoiding sharing towels.

7 Review is unnecessary for most mild/moderate adult cases, although patients should be cautioned to seek further advice in the event of deterioration.

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8 Statutory notification of public health authorities may be required locally in some cases.

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Adult chlamydial conjunctivitis

Pathogenesis

Chlamydia trachomatis (Fig. 5.5) is a species of Chlamydiae, a phylum of bacteria that cannot replicate extracellularly and hence depend on host cells. They exist in two principal forms: (a) a robust infective extracellular ‘elementary body’ and (b) a fragile intracellular replicating ‘reticular body’. Adult chlamydial (inclusion) conjunctivitis is an oculogenital infection usually caused by serovars (serological variants) D-K of C. trachomatis, and affects 5–20% of sexually active young adults in western countries. Transmission is by autoinoculation from genital secretions although eye-to-eye spread probably accounts for about 10% of cases. The incubation period is about 1 week.

Fig. 5.5 Classification of Chlamydia trachomatis

Urogenital infection

1 In males chlamydial infection is the most common cause of non-gonococcal urethritis (NGU), also termed non-specific urethritis (NSU). It should be noted that the latter term is also sometimes used to mean urethritis in which both gonococcal and chlamydial infection have been ruled out. Chlamydial urethritis is frequently asymptomatic in men. C. trachomatis may also cause epididymitis, and can act as a trigger for Reiter’s disease.

2 In females chlamydial urethritis typically causes dysuria and discharge. It may progress to pelvic inflammatory disease (PID), carrying a risk of infertility; 5–10% of women with PID develop perihepatitis (Fitz-Hugh–Curtis syndrome).

Diagnosis

1 Symptoms consist of the subacute onset of unilateral or bilateral redness, watering and discharge. Untreated, the conjunctivitis becomes chronic, and though self-limiting may persist for several months. It is important to enquire about sexual exposure if chlamydial conjunctivitis is suspected.

2 Signs

• Watery or mucopurulent discharge.

• Large follicles are often most prominent in the inferior fornix (Fig. 5.6A) and may also involve the upper tarsal conjunctiva (Fig. 5.6B).

• Superficial punctate keratitis is common.

• Peripheral subepithelial corneal infiltrates may appear 2–3 weeks after the onset of conjunctivitis (Fig. 5.6C).

• Tender preauricular lymphadenopathy.

• Chronic cases have less prominent follicles and may develop mild conjunctival scarring and superior corneal pannus (Fig. 5.6D).

3 Investigations. Tarsal conjunctival scrapings are obtained using a spatula or the blunt end of a scalpel blade.

• Nucleic acid amplification tests such as PCR are likely to be the investigation of choice in time but validation in ocular specimens is at present limited.

• Giemsa staining for basophilic intracytoplasmic bodies is performed by applying scrapings onto a glass slide.

• Direct immunofluorescence (Fig. 5.6E) detects free elementary bodies with about 90% sensitivity and specificity.

• Enzyme immunoassay for direct antigen detection is also useful.

• McCoy cell culture (Fig. 5.6F) is highly specific.

• It is also useful to take swabs for bacterial culture, and serology may be helpful in selected cases.

Fig. 5.6 Adult chlamydial conjunctivitis. (A) Large forniceal follicles; (B) superior tarsal follicles; (C) peripheral corneal infiltrates; (D) superior pannus; (E) elementary bodies seen on direct immunofluorescence; (F) McCoy cell culture shows glycogen-positive inclusion bodies

(Courtesy of J Harry and G Misson, from Clinical Ophthalmic Pathology Butterworth-Heinemann 2001 – fig. E)

Treatment

1 Referral to a genitourinary specialist is mandatory, particularly for the exclusion of other sexually transmitted infections, contact tracing and pregnancy testing.

2 Systemic therapy involves one of the following:

• Azithromycin 1 g repeated after 1 week is generally the drug of choice, although a second or a third dose is required in 30% of cases.

• Doxycycline 100 mg b.d. for 10 days (tetracyclines are relatively contraindicated in pregnancy/breastfeeding and in children under 12 years of age).

• Erythromycin, amoxicillin and ciprofloxacin are alternatives.

3 Topical antibiotics such as erythromycin or tetracycline ointment are sometimes used to achieve rapid relief of ocular symptoms.

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4 Reduction of transmission risk involves abstinence of sexual contact until completion of treatment (1 week after azithromycin), together with other precautions as for any infectious conjunctivitis.

It is important to be aware that symptoms commonly take weeks to settle, and follicles and corneal infiltrates can take months to resolve due to a prolonged hypersensitivity response to chlamydial antigen.

Trachoma

Pathogenesis

Trachoma is the leading cause of preventable irreversible blindness in the world. It is related to poverty, overcrowding, and poor hygiene, the morbidity being a consequence of the establishment of re-infection cycles within communities. Whereas an isolated episode of trachomatous conjunctivitis may be relatively innocuous, recurrent infection elicits a chronic immune response consisting of a cell-mediated delayed hypersensitivity (type IV) reaction to the intermittent presence of chlamydial antigen and can lead to loss of sight. The family childcare group is the most important re-infection reservoir, and consequently young children are particularly vulnerable. The fly is an important vector, but there may be direct transmission from eye or nasal discharge. Trachoma is associated principally with infection by serovars A, B, Ba, and C of Chlamydia trachomatis, but the serovars D-K conventionally associated with adult inclusion conjunctivitis, and other species of the Chlamydiaceae family such as Chlamydophila psittaci and Chlamydophila pneumoniae have also been implicated.

Diagnosis

The features of trachoma are divided into the ‘active’ inflammatory stage and the ‘cicatricial’ chronic stage, with considerable overlap.

1 Active trachoma is most common in pre-school children and is characterized by the following:

• Mixed follicular/papillary conjunctivitis (Fig. 5.7A) associated with a mucopurulent discharge. In children under the age of 2 years the papillary component may predominate.

• Superior epithelial keratitis and pannus formation (Fig. 5.7B).

2 Cicatricial trachoma is most prevalent in middle age.

• Linear or stellate conjunctival scars in mild cases (Fig. 5.7C), or broad confluent scars (Arlt lines – Fig. 5.7D) in severe disease.

• Although the entire conjunctiva is involved, the effects are most prominent on the upper tarsus.

• Superior limbal follicles may resolve to leave a row of shallow depressions (Herbert pits – Fig. 5.7E).

• Trichiasis, distichiasis, corneal vascularization and cicatricial entropion (Fig. 5.7F).

• Severe corneal opacification.

• Dry eye caused by destruction of goblet cells and the ductules of the lacrimal gland.

3 Investigations are rarely used and the diagnosis is made on clinical grounds.

Fig. 5.7 Trachoma. (A) Mixed follicular-papillary conjunctivitis; (B) severe pannus; (C) linear scars; (D) Arlt line; (E) Herbert pits; (F) corneal scarring and vascularization, and cicatricial entropion

(Courtesy of R Bates – fig. E; C Barry – fig. F)

Table 5.1 WHO grading of trachoma

TF = trachomatous inflammation (follicular): five or more follicles (>0.5 mm) on the superior tarsus

TI = trachomatous inflammation (intense):diffuse involvement of the tarsal conjunctiva, obscuring 50% or more of the normal deep tarsal vessels; papillae are present

TS = trachomatous conjunctival scarring: easily visible fibrous white tarsal bands

TT = trachomatous trichiasis: at least one lash touching the globe

CO = corneal opacity sufficient to blur details of at least part of the pupillary margin

Management

The SAFE strategy for trachoma management supported by the WHO and other agencies encompasses Surgery for trichiasis, Antibiotics for active disease, Facial hygiene, and Environmental improvement.

1 Antibiotics should be administered to those affected and to all family members. A single antibiotic course is not always effective in eliminating infection in an individual, and communities may need to receive annual treatment to suppress infection.

• A single dose of azithromycin (20 mg/kg up to 1g) is the treatment of choice.

• Erythromycin 500 mg b.d. for 14 days is an alternative for women of childbearing age.

• Topical 1% tetracycline ointment is less effective than oral treatment; it should be given for 6 weeks.

2 Facial cleanliness is a critical preventative measure.

3 Environmental improvement such as access to adequate water and sanitation, as well as control of flies, is important.

4 Surgery is aimed at relieving entropion and trichiasis and maintaining complete lid closure with bilamellar tarsal rotation.

Neonatal conjunctivitis

Neonatal conjunctivitis (ophthalmia neonatorum) is defined as conjunctival inflammation developing within the first month of life. It is the most common infection of any kind in neonates, occurring in up to 10%. It is identified as a specific entity distinct from conjunctivitis in older infants because it is often the result of infection transmitted from mother to infant during delivery. Notification of neonatal conjunctivitis to the local public health authority is a statutory requirement in many countries.

Causes

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• C. trachomatis, N. gonorrhoeae (now rare in developed countries) and occasionally herpes simplex virus (typically HSV-2), which may be associated with severe ocular or systemic complications.

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• Staphylococci are usually responsible for mild conjunctivitis; other bacteria include Streptococci, Haemophilus influenzae and various Gram-negative organisms.

• Topical preparations used as prophylaxis against infection (see below), may themselves cause conjunctival irritation.

• Despite poor neonatal tear production, a persistently mildly watery eye with recurrent mild bacterial conjunctivitis may be secondary to congenital nasolacrimal obstruction.

Diagnosis

1 Timing of onset

• Chemical irritation: first few days.

• Gonococcal: first week.

• Staphylococci and other bacteria: end of the first week.

• Herpes simplex: 1–2 weeks.

• Chlamydia: 1–3 weeks.

2 History

• Instillation of a prophylactic chemical preparation.

• Parental symptoms of sexually transmitted infections.

• Recent conjunctivitis in close contacts.

• Systemic illness such as pneumonitis, rhinitis and otitis in chlamydial infection, skin vesicles and features of encephalitis in herpes simplex.

• Prior persistent watering without inflammation may indicate an uncanalized nasolacrimal duct.

3 Signs

• The type of discharge varies according to the underlying cause.

• Reflux of mucopurulent material on pressure over the lacrimal sac is suggestive of delayed canalization of the lacrimal duct.

• Severe eyelid oedema occurs in gonococcal infection (Fig. 5.8).

• Eyelid and periocular vesicles may occur in HSV infection.

• Keratitis in gonococcal or HSV infection.

4 Investigations are tailored to the clinical picture.

• Conjunctival scrapings applied to a glass slide for Gram and Giemsa staining (see bacterial and chlamydial conjunctivitis above). Multinucleated giant cells may be present on Gram stain in HSV infection.

• Conjunctival swabs with a calcium alginate swab or a sterile cotton-tipped applicator, for standard bacterial culture and chocolate agar or Thayer–Martin for N. gonorrhoeae).

• Epithelial cells infected with HSV may show eosinophilic intranuclear inclusions on Papanicolaou smear.

• Separate conjunctival scrapings should be taken for nucleic acid amplification testing (e.g. PCR), particularly for chlamydia.

• Conjunctival scrapings or fluid from skin vesicles can be sent for viral culture for HSV.

• Specimens should be taken prior to fluorescein instillation if immunofluorescent testing is planned.

Fig. 5.8 Eyelid oedema and severe discharge in neonatal conjunctivitis

Treatment

1 Prophylaxis is routinely performed but there is no standard protocol.

• A single instillation of povidone-iodine 2.5% solution is effective against the common pathogens.

• Erythromycin 0.5% or tetracycline 1% ointment is also used.

• Silver nitrate 1% solution agglutinates gonococci and is still utilized in areas where gonococcal infection is common. It should be administered in conjunction with a single intramuscular dose of benzylpenicillin when maternal infection is present.

2 Chemical conjunctivitis does not require treatment apart from artificial tears.

3 Mild conjunctivitis (sticky eye) is very common in neonates and may require a broad-spectrum topical antibiotic such as chloramphenicol or fusidic acid.

4 Moderate to severe cases should be investigated as above.

• If bacteria are evident on Gram stain, a broad-spectrum topical antibiotic should be used until sensitivities are available.

• Chlamydial infection is treated with oral erythromycin for two weeks. Erythromycin or tetracycline ointment can be used in addition.

5 Severe conjunctivitis, or when systemic illness is suspected, requires hospital admission.

• Gonococcal conjunctivitis is treated systemically with a third-generation cephalosporin. Co-treatment for chlamydia is prudent.

• Herpes simplex infection should always be regarded as a systemic condition and is treated with high-dose intravenous aciclovir under paediatric specialist care. Early diagnosis and treatment of encephalitis may be life-saving or prevent serious neurological disability. Topical aciclovir may be considered in addition.

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6 Specialist advice from a microbiologist or paediatrician should be sought as appropriate in patients with severe involvement, particularly with systemic features. A genitourinary specialist referral for the mother and her sexual contacts is important when a sexually-transmitted infection is diagnosed; the neonate should also be screened for other sexually-transmitted infection.

Viral conjunctivitis

Adenoviral conjunctivitis

Pathogenesis

Viral conjunctivitis is most frequently caused by an adenovirus (a non-enveloped double-stranded DNA virus). Infection may be sporadic or it may occur in epidemics in workplaces (including hospitals), schools and swimming pools. The spread of this highly contagious disease is facilitated by the ability of viral particles to survive on dry surfaces for weeks, and by the fact that viral shedding may occur for many days before clinical features are apparent. Transmission is generally by contact with respiratory or ocular secretions, including via fomites such as contaminated towels.

Presentation

The spectrum of viral conjunctivitis varies from mild subclinical disease to severe inflammation with significant morbidity. There will often be a history of a close contact with acute conjunctivitis.

1 Non-specific acute follicular conjunctivitis is the most common and is caused by a range of adenoviral serological variants. Ocular involvement is generally milder than in other forms of adenoviral infection although accompanying (usually mild) systemic symptoms such as a sore throat or cold are frequent.

2 Pharyngoconjunctival fever (PCF) is caused by adenovirus serovars 3, 4 and 7. It is spread by droplets within families with upper respiratory tract infection. Keratitis develops in about 30% of cases but is seldom severe.

3 Epidemic keratoconjunctivitis (EKC) is caused by adenovirus serovars 8, 19 and 37. It is the most severe type and is associated with keratitis in about 80% of cases.

4 Chronic/relapsing adenoviral conjunctivitis, characterized by chronic non-specific follicular/papillary lesions, is rare but can persist for years.

Signs

1 Eyelid oedema and tender pre-auricular lymphadenopathy.

2 Prominent conjunctival hyperaemia and follicles (Fig. 5.9A).

3 Severe inflammation may be associated with conjunctival haemorrhages (usually petechial in adenoviral infection), chemosis, membranes (rare) and pseudomembranes (Fig. 5.9B)

4 Pseudomembranes or membranes may leave mild conjunctival scarring after resolution (Fig. 5.9C)

5 Keratitis in adenoviral disease is characterized by the following:

• Epithelial microcysts (non-staining) are common during the early stage.

• Punctate epithelial keratitis (Fig. 5.9D) may develop within 7–10 days of the onset of symptoms and resolves within 2 weeks.

• Focal white subepithelial/anterior stromal infiltrates may develop beneath the fading epithelial lesions, probably as an immune response to the virus (Fig. 5.9E), and may persist or recur over months or years (Fig. 5.9F).

6 Mild anterior uveitis is uncommon.

Fig. 5.9 Adenoviral keratoconjunctivitis. (A) Follicular conjunctivitis; (B) pseudomembrane; (C) mild residual scarring; (D–F) keratitis (see text)

(Courtesy of S Tuft – figs B, C and D)

Differential diagnosis

1 Acute haemorrhagic conjunctivitis typically occurs in tropical areas and usually caused by enterovirus and coxsackievirus. It has a rapid onset and resolves within 1–2 weeks; conjunctival haemorrhages are characteristic.

2 Herpes simplex virus (HSV) can cause a follicular conjunctivitis, particularly in primary infection, which is usually unilateral and often associated with skin vesicles

3 Systemic viral infections such as those common in childhood, e.g. varicella, measles and mumps, can be associated with follicular conjunctivitis.Varicella-zoster virus causes a conjunctivitis as part of ophthalmic shingles. An HIV conjunctivitis is also recognized.

Management

Spontaneous resolution usually occurs within 2–3 weeks.

1 Investigations are generally unnecessary, although they can be considered if the diagnosis is in doubt or the condition fails to resolve.

• Giemsa stain shows predominantly mononuclear cells in adenoviral conjunctivitis and multinucleated giant cells in herpetic infection.

• Nucleic acid amplification techniques such as PCR are sensitive and specific for viral DNA.

• Viral culture with isolation is the reference standard but is expensive and fairly slow (days–weeks), and requires specific transport media. Sensitivity is variable but specificity around 100%.

• A ‘point-of-care’ immunochromatography test takes 10 minutes to detect adenoviral antigen in tears; sensitivity and specificity are excellent.

2 Reduction of transmission risk by meticulous hand hygiene, avoiding eye rubbing and towel sharing. There should also be scrupulous disinfection of instruments and clinical surfaces after examination of an infected patient (e.g. sodium hypochlorite, povidone-iodine).

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3 Topical steroids such as prednisolone 0.5% q.i.d. may be required for severe membranous or pseudomembranous adenoviral conjunctivitis. Symptomatic keratitis may require weak topical steroids but these should be used with caution as they do not speed resolution but only suppress inflammation, and lesions commonly recur after premature discontinuation. Steroids may enhance viral replication and extend the period during which the patient remains infectious. Intraocular pressure should be monitored if treatment is prolonged.

4 Other measures

• Discontinuation of contact lens wear until resolution of symptoms.

• Artificial tears q.i.d. may be useful for symptomatic relief. Preservative-free preparations may give superior comfort, and if supplied in single-dose units may reduce transmission risk.

• Cold (or warm) compresses for symptomatic relief.

• Removal of symptomatic pseudomembranes or membranes.

• Topical antibiotics if secondary bacterial infection is suspected.

• Povidone-iodine is very effective against free (although less so against intracellular) adenovirus, and has been proposed as a means of decreasing infectivity.

Molluscum contagiosum conjunctivitis

Pathogenesis

Molluscum contagiosum is a skin infection caused by a human specific double-stranded DNA poxvirus which typically affects otherwise healthy children, with a peak incidence between the ages of 2 and 4 years. Transmission is by contact, with subsequent autoinoculation. The eyelash line should be examined carefully in patients with chronic conjunctivitis so as not to overlook a molluscum lesion.

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Diagnosis

1 Presentation is with chronic unilateral ocular irritation and mild discharge.

2 Signs

• A pale, waxy, umbilicated nodule on the lid margin associated with follicular conjunctivitis and mild mucoid discharge (Fig. 5.10A).

• Bulbar nodules (Fig. 5.10B) and multiple cutaneous lesions that may be confluent (Fig. 5.10C) may occur in immunocompromised patients.

• Untreated long-standing cases may develop a fine epithelial keratitis and sometimes pannus.

Fig. 5.10 (A) Follicular conjunctivitis associated with a molluscum eyelid lesion; (B) molluscum lesions on the bulbar conjunctiva; (C) extensive confluent molluscum lesions in an HIV positive patient

(Courtesy of JH Krachmer; MJ Mannis and EJ Holland, from Cornea, Mosby 2005 – fig. B; D Smit – fig. C)

Treatment

Although the lesions are self-limiting in the immunocompetent, removal is often necessary to address secondary conjunctivitis or for cosmetic reasons. Expression is facilitated by making a small nick in the skin at the margin of the lesion with the tip of a needle.

Allergic conjunctivitis

Atopy is a genetically determined predisposition to hypersensitivity reactions upon exposure to specific environmental antigens. Clinical manifestations include the various forms of allergic conjunctivitis, as well as hay fever (seasonal allergic rhinitis), asthma and eczema. Allergic conjunctivitis is a Type I (immediate) hypersensitivity reaction, mediated by degranulation of mast cells in response to the action of IgE; there is evidence of an element of Type IV hypersensitivity in at least some forms.

Acute allergic conjunctivitis

Acute allergic conjunctivitis is a common condition caused by an acute conjunctival reaction to an environmental allergen, usually pollen. It is typically seen in younger children after playing outside in spring or summer.

1 Presentation is with acute itching and watering, associated with severe chemosis (Fig. 5.11).

2 Treatment is not usually required and the conjunctival swelling settles within hours as the acute increase in vascular permeability resolves. Cool compresses can be used and a single drop of adrenaline 0.1% may reduce extreme chemosis.

Fig. 5.11 Severe chemosis in acute allergic conjunctivitis

Seasonal and perennial allergic conjunctivitis

Seasonal and perennial allergic conjunctivitis are subacute conditions that differ from each other by the timing of exacerbations because of different stimulating allergens in each.

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1 Seasonal allergic conjunctivitis (‘hay fever eyes’), worse during the spring and summer, is the more common. The most frequent allergens are tree and grass pollens, although the specific allergen varies with geographic location.

2 Perennial allergic conjunctivitis causes symptoms throughout the year, generally worse in the autumn when exposure to house dust mites, animal dander and fungal allergens is greatest. It is less common and tends to be milder than the seasonal form.

Diagnosis

1 Presentation is with transient acute or subacute attacks of redness, watering and itching, associated with sneezing and nasal discharge.

2 Signs, which typically resolve completely between episodes, consist of conjunctival hyperaemia and a relatively mild papillary reaction, variable chemosis and lid oedema.

3 Investigations are generally not performed although conjunctival scraping in more active cases may demonstrate the presence of eosinophils.

Treatment

1 Artificial tears for mild symptoms.

2 Mast cell stabilizers (sodium cromoglicate, nedocromil sodium, lodoxamide) need to be used for a few days before exerting maximal effect, but are suitable (except lodoxamide) for long-term use if required.

3 Antihistamines (emedastine, epinastine, levocabastine, bepotastine) can be used for symptomatic exacerbations and are as effective as mast cell stabilizers.

4 Combined preparation of an antihistamine and a vasoconstrictor (antazoline with xylometazoline – Otrivin-Antistin®).

5 Dual action antihistamine and mast cell stabilizers (azelastine, ketotifen, olopatadine) are often very effective for exacerbations.

6 Topical steroids are effective but rarely necessary.

7 Oral antihistamines may be indicated for severe symptoms. Some, such as diphenhydramine, cause significant drowsiness and may be useful in aiding sleep; others such as loratadine have less sedative action.

Vernal keratoconjunctivitis

Pathogenesis

Vernal keratoconjunctivitis (VKC) is a recurrent bilateral disorder in which both IgE- and cell-mediated immune mechanisms play important roles. It primarily affects boys and onset is generally from about the age of 5 years onwards (mean age 7 years). Ninety-five per cent of cases remit by the late teens although many of the remainder develop atopic keratoconjunctivitis. VKC is rare in temperate regions but relatively common in warm dry climates such as the Mediterranean, sub-Saharan Africa, and the Middle East. In temperate regions over 90% of patients have other atopic conditions such as asthma and eczema and two-thirds of cases have a family history of atopy. VKC often occurs on a seasonal basis, with a peak incidence over late spring and summer, although there may be mild perennial symptoms.

Classification

1 Palpebral VKC primary involves the upper tarsal conjunctiva. It may be associated with significant corneal disease as a result of the close apposition between the inflamed conjunctiva and the corneal epithelium.

2 Limbal disease typically affects black and Asian patients.

3 Mixed VKC has features of both palpebral and limbal disease.

Diagnosis

The diagnosis is clinical and investigations are generally not indicated.

1 Symptoms consist of intense itching, which may be associated with lacrimation, photophobia, a foreign body sensation, burning and thick mucoid discharge. Increased blinking is common.

2 Palpebral disease

• Early-mild disease is characterized by conjunctival hyperaemia and diffuse papillary hypertrophy on the superior tarsus (Fig. 5.12A).

• Macropapillae (<1 mm) have a flat-topped polygonal appearance reminiscent of cobblestones (Fig. 5.12B).

• Progression to giant papillae (>1 mm) can occur, as adjacent smaller lesions amalgamate when dividing septa rupture.

• Mucus deposition between giant papillae (Fig. 5.12C).

• Decreased disease activity is characterized by milder conjunctival injection and decreased mucus production (Fig. 5.12D).

3 Limbal disease

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• Gelatinous limbal conjunctiva papillae that may be associated with transient apically-located white cellular collections (Horner-Trantas dots – Fig. 5.13A-C).

• In tropical regions limbal disease may be very severe (Fig. 5.13D).

4 Keratopathy is more frequent in palpebral disease and may take the following forms:

a Superior punctate epithelial erosions associated with sheets of mucus on the superior cornea (Fig. 5.14A).

b Epithelial macroerosions (Fig. 5.14B) caused by a combination of epithelial toxicity from inflammatory mediators and a direct mechanical effect from papillae.

c Plaques (Fig. 5.14C) and ‘shield’ ulcers (Fig. 5.14D) may develop in palpebral or mixed disease when the exposed Bowman membrane becomes coated with mucus and calcium phosphate, leading to inadequate wetting and delayed re-epithelialization. This development is serious and warrants urgent attention to prevent secondary bacterial infection.

d Subepithelial scars that are typically grey and oval, and may affect vision (Fig. 5.14E).

e Pseudogerontoxon can develop in recurrent limbal disease. It is characterized by a paralimbal band of superficial scarring resembling arcus senilis, adjacent to a previously inflamed segment of the limbus (Fig. 5.14F).

f Other manifestations

• Vascularization does not tend to be prominent, though some peripheral superficial vessel ingrowth is common, especially superiorly.

• Keratoconus and other forms of corneal ectasia are more common in VKC.

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• Herpes simplex keratitis is more common than average, though less so than in atopic keratoconjunctivitis (AKC). It can be aggressive and is occasionally bilateral.

5 Eyelid disease is usually mild, in contrast to AKC.

Fig. 5.12 Palpebral vernal disease. (A) Diffuse papillary hypertrophy; (B) macropapillae; (C) giant papillae and mucus; (D) relatively inactive disease

(Courtesy of S Tuft – figs B and D)

Fig. 5.13 Limbal vernal disease. (A) Sparse limbal papillae; (B) papillae with Horner–Trantas dots; (C) extensive papillae; (D) extremely severe involvement

(Courtesy of S Tuft – fig. B)

Fig. 5.14 Keratopathy in vernal disease. (A) Superior punctate erosions and sheets of mucus; (B) macroerosion; (C) early plaque formation; (D) plaque and ‘shield’ ulcer; (E) oval subepithelial scarring; (F) pseudogerontoxon and limbal papillae

(Courtesy of S Tuft – figs A, B, C and F)

Atopic keratoconjunctivitis

Pathogenesis

AKC is a rare bilateral disease that typically develops in adulthood (peak incidence 30–50 years) following a long history of eczema. Asthma is also extremely common in these patients. About 5% have suffered from childhood VKC. There is little or no gender preponderance. AKC tends to be chronic and unremitting with a relatively low expectation of eventual resolution, and is associated with significant visual morbidity. Whereas VKC is more frequently seasonal, AKC tends to be perennial, although it is often worse in the winter. Patients are sensitive to a wide range of airborne environmental allergens.

Diagnosis

The distinction between AKC and VKC is clinical.

1 Symptoms are similar to those in VKC, but are frequently more severe and unremitting.

2 Eyelids

• Skin changes (Fig. 5.15A) consist of erythema, dryness, scaliness and thickening, sometimes with fissuring, and scratches (‘excoriation’) due to intense itching.

• Associated chronic staphylococcal blepharitis and madarosis are common.

• Keratinization of the lid margin.

• Hertoghe sign is characterized by absence of the lateral portion of the eyebrows.

• Tightening of the facial skin may cause lower lid ectropion and epiphora.

3 Conjunctival involvement is preferentially inferior palpebral, whereas in VKC it is worse superiorly.

• Discharge is generally more watery than the stringy mucoid discharge in VKC.

• Papillae are initially smaller than in VKC although larger lesions may develop later.

• Diffuse conjunctival infiltration and scarring may give a whitish, featureless appearance (Fig. 5.15B).

• Cicatricial changes can lead to moderate symblepharon formation, forniceal shortening (Fig. 5.15C) and keratinization of the caruncle (Fig. 5.15D).

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• Limbal involvement similar to that of limbal VKC can be seen, including Horner–Trantas dots.

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4 Keratopathy

a Punctate epithelial erosions over the inferior third of the cornea are common (Fig. 5.15E).

b Persistent epithelial defects (Fig. 5.15F), sometimes with associated focal thinning, can occasionally progress to perforation.

c Plaque formation may occur.

d Peripheral vascularization (see Fig. 5.15F) and stromal scarring are more common than in VKC.

e Other manifestations

• Predisposition to secondary bacterial and fungal infection, and to aggressive herpes simplex keratitis.

• Keratoconus is common (about 15%) and as with VKC it is thought to be secondary to chronic ocular rubbing.

5 Cataract

• Presenile shield-like anterior or posterior subcapsular cataracts are common and may be exacerbated by long-term steroid therapy.

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• Because of the high lid margin carriage of S. aureus, cataract surgery carries an increased risk of endophthalmitis.

6 Retinal detachment is more common than in the general population.

Fig. 5.15 Atopic disease. (A) Severe eyelid involvement; (B) infiltration and scarring of the tarsal conjunctiva; (C) forniceal shortening; (D) keratinization of the caruncle; (E) punctate epithelial erosions; (F) persistent epithelial defect and peripheral corneal vascularization

(Courtesy of S Tuft)

Treatment of VKC and AKC

The management of VKC does not differ substantially from that of AKC, although the latter is generally less responsive and requires more intensive and prolonged treatment.

General measures

1 Allergen avoidance, if possible. An allergy specialist opinion can be requested if appropriate; allergen patch testing is sometimes useful, but often gives non-specific findings.

2 Cool compresses may be helpful.

3 Lid hygiene should be used for associated staphylococcal blepharitis. Moisturizing cream such as E45 can be applied to dry fissured skin.

Local treatment

1 Mast cell stabilizers may reduce the frequency of acute exacerbations and the need for steroids and so form the basis of most regimens, although they are seldom effective in isolation. Several days of treatment are needed for a reasonable response and in some cases long-term therapy may be needed (lodoxamide is not licensed for long-term use). In some patients adding a NSAID (ketorolac, diclofenac) may give added benefit.

2 Antihistamines are suitable for acute exacerbations but generally not for long-term use. A trial of several different agents may be worthwhile.

3 Combined preparations of an antihistamine and a vasoconstrictor usually offer only limited relief whereas dual action antihistamine/mast cell stabilizers are often effective.

4 Steroids are used for (a) severe exacerbations of conjunctivitis and (b) significant keratopathy in which reducing conjunctival activity leads to corneal improvement.

• Steroids (fluorometholone 0.1%, rimexolone 1%, prednisolone 0.5% or loteprednol etabonate 0.2% or 0.5%) are usually prescribed in short but intensive courses, aiming for prompt tapering. Although the risk of elevation of intraocular pressure is low, monitoring is advisable if long-term medication is necessary, particularly in AKC.

• Stronger preparations such as prednisolone 1% can be used but carry a higher risk of steroid-induced glaucoma.

• Supratarsal steroid injection may be considered in severe palpebral disease, for non-compliance or for patients resistant to conventional therapy. The injection is given into the conjunctival surface of the anaesthetized everted upper eyelid; 0.1 mL of betamethasone sodium phosphate 4 mg/mL (Betnesol), dexamethasone 4 mg/mL or triamcinolone 40 mg/mL is given.

5 Immune modulators

a Ciclosporin 0.05% b.d. may be indicated if steroids are ineffective, inadequate or poorly tolerated, or as a steroid-sparing agent in patients with severe disease. The drug may cause ocular irritation and blurred vision when used for several weeks and relapses may occur if it is stopped suddenly. Its efficacy as a first line agent for long-term therapy requires further study.

b Tacrolimus 0.03% ointment can be effective in AKC for severe eyelid disease. Instillation into the fornices has been effective in modulating conjunctival inflammation in refractory cases.

6 Other measures

a Antibiotics are used in conjunction with steroids in severe keratopathy to prevent or treat bacterial infection.

b Acetylcysteine is a mucolytic agent that is useful in VKC for dissolving mucus filaments and deposits, and addressing early plaque formation.

Systemic treatment

1 Antihistamines help itching, promote sleep and reduce nocturnal eye rubbing. Because other inflammatory mediators are involved besides histamines, effectiveness is not assured.

2 Antibiotics (doxycycline 50–100 mg daily for 6 weeks or azithromycin 500 mg once daily for 3 days) to reduce blepharitis-aggravated inflammation, usually in AKC.

3 Immunosuppressive agents (e.g. steroids, ciclosporin, tacrolimus, azathioprine) may be effective at relatively low doses in AKC unresponsive to other measures. Short courses of high-dose steroids may be necessary to achieve rapid control in severe disease. Monoclonal antibodies against T cells have shown some promise in refractory cases.

4 Aspirin may be useful in VKC, although the risk of Reye’s syndrome means it should be avoided in children and adolescents (the group predominantly affected by VKC).

Surgery

1 Bandage contact lens wear may be appropriate to aid the healing of persistent epithelial defects.

2 Superficial keratectomy may be required to remove plaques or debride shield ulcers and allow epithelialization. Medical treatment must be maintained until the cornea has re-epithelialized in order to prevent recurrences. Excimer laser phototherapeutic keratectomy is an alternative.

3 Surface maintenance-restoration surgery such as amniotic membrane overlay grafting or lamellar keratoplasty, or eyelid procedures such as botulinum toxin-induced ptosis or lateral tarsorrhaphy, may be required for severe persistent epithelial defects or ulceration. Gluing may be appropriate for focal (‘punched-out’) corneal perforations.

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Giant (mechanically-induced) papillary conjunctivitis

Pathogenesis

Mechanically-induced papillary conjunctivitis, the severe form of which is known as giant papillary conjunctivitis (GPC), can occur secondary to a variety of mechanical stimuli of the tarsal conjunctiva. It is most frequently seen with contact lens (CL) wear, when it is termed contact lens-associated papillary conjunctivitis (CLPC). The risk is increased by the build-up of proteinaceous deposits and cellular debris on the contact lens surface (Fig. 5.16). Ocular prostheses (Fig. 5.17), exposed sutures and scleral buckles, corneal surface irregularity and filtering blebs can all be responsible. A related phenomenon is the so-called ‘mucus fishing syndrome’, when, in a variety of underlying anterior segment disorders, patients develop or exacerbate a chronic papillary reaction due to repetitive manual removal of mucus.

Fig. 5.16 Contact lens deposits

Fig. 5.17 Ocular prosthesis causing giant papillary conjunctivitis

Diagnosis

1 Symptoms consist of a foreign body sensation, redness, itching, increased mucus production, blurring and loss of CL tolerance. Symptoms may be worse after lens removal. Patients should be questioned about CL cleaning and maintenance.

2 Signs

• Variable mucous discharge.

• Protein deposits on the CL.

• Excessive CL mobility due to upper lid capture.

• Superior tarsal hyperaemia and initially fine-medium size papillae (>0.3 mm).

• Focal apical ulceration and whitish scarring may develop on larger papillae in advanced cases.

• Keratopathy is rare because of the relatively subdued secretion of inflammatory cytokines.

• Ptosis may occur mainly as a result of irritative spasm and tissue laxity secondary to chronic inflammation.

Treatment

Other causes of conjunctival papillae should be excluded, as well as CL intolerance due to other causes such as solutions and dry eyes.

1 Remove the stimulus

• CL wear should be discontinued for several weeks and the current lenses replaced.

• For mild–moderate disease, this may be adequate for resolution, sometimes in conjunction with reduced wearing time.

• In severe disease a longer interval without lens wear may be needed.

• Removal of other underlying causes such as exposed sutures or scleral buckle.

• Assessment of the status and fit of ocular prosthesis.

• Refashioning of filtering blebs or glaucoma drainage devices.

2 Ensure effective cleaning of CL or prosthesis

• Changing the type of CL solution, particularly preservative-containing preparations.

• Switching to monthly then daily disposable CL if the condition persists after renewing non-disposable lenses.

• Rigid lenses carry a lesser risk of CLPC (5%) because they are easier to clean effectively.

• Cessation of CL wear and substituting spectacles or refractive surgery for severe or refractory disease.

• Regular (at least weekly) use of contact lens protein removal tablets.

• Prostheses should be cleaned and polished.

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3 Topical

• Mast cell stabilizers should be non-preserved in patients wearing soft contact lenses, or can be instilled when the lenses are not in the eye, with a delay of perhaps half an hour after drop instillation prior to lens insertion. Most can be continued long-term if necessary.

• Antihistamines, non-steroidal anti-inflammatory agents and combined antihistamines/mast cell stabilizers may each be of benefit.

• Topical steroids can be used for the acute phase of resistant cases, particularly those where effective removal of the stimulus is difficult, as in bleb-related disease.

Conjunctivitis in blistering mucocutaneous disease

Mucous membrane pemphigoid

Definition

Mucous membrane pemphigoid (MMP), also known as cicatricial pemphigoid (CP), comprises a group of chronic autoimmune mucocutaneous blistering diseases characterized by linear antibody and complement deposition at epithelial basement membranes. A wide range of epithelial tissues can be involved including the skin and mucous membranes of the mouth, nasopharynx, upper airways, genitalia, and upper and lower gastrointestinal tract, as well as the conjunctiva. Particular clinical forms of MMP tend preferentially to involve specific target tissues or body regions such as bullous pemphigoid (BP) that shows a predilection for skin, although frequently also affects the mouth and other tissues. Ocular cicatricial pemphigoid (OCP) involves the conjunctiva in the majority of cases and causes progressive scarring (cicatrization). The disease typically presents in old age and affects females more commonly than males by a 2 : 1 ratio. Other causes of cicatrizing conjunctivitis are set out in Table 5.2.

Table 5.2 Causes of conjunctival cicatrization

• Mucous membrane pemphigoid

• Stevens–Johnson syndrome-toxic epidermal necrolysis (Lyell syndrome)

• Atopic (and less commonly vernal) keratoconjunctivitis

• Conjunctival chemical and thermal burns

• Severe bacterial or viral conjunctivitis

• Trachoma

• Drug-induced (‘pseudopemphigoid’)

• Other: epidermolysis bullosa, pemphigus vulgaris, linear IgA disease, dermatitis herpetiformis, lichen planus, porphyria cutanea tarda, xeroderma pigmentosum, scleroderma, xerophthalmia (vitamin A deficiency)

Pathogenesis

An unknown trigger (possibly contact with a particular micro-organism) in genetically predisposed individuals leads to a Type II hypersensitivity response with antibodies binding at the basement membrane zone (BMZ), the activation of complement and recruitment of inflammatory cells. A characteristic of the acute phase of the inflammatory process is localized separation of the epidermis from the dermis at the BMZ. The release of cytokines causes fibroblast activation with consequent progression to scarring. Different clinical forms of MMP tend to be associated with differing target antigens. In bullous pemphigoid, it is one or more hemidesmosomal glycoproteins, and in many cases of OCP, a component of an integrin (a protein mediating cell–cell and cell–matrix interaction) is responsible.

Ocular features

1 Presentation is with the insidious onset of non-specific conjunctivitis which is bilateral, but frequently asymmetrical. Because of its rarity, the diagnosis is often overlooked or there may be misdiagnosis, with specific treatment being delayed.

2 Conjunctiva

• Papillary conjunctivitis, diffuse hyperaemia and oedema, and necrosis in severe cases (Fig. 5.18A).

• Fine lines of subconjunctival fibrosis and shortening of the inferior fornices (Fig. 5.18B).

• Flattening of the plica and keratinization of the caruncle (Fig. 5.18C).

• Symblepharon (plural symblephara) is an adhesion between the bulbar and palpebral conjunctiva (Fig. 5.18D).

• Dry eye is caused by a combination of destruction of goblet cells and accessory lacrimal glands as well as occlusion of the main lacrimal ductules.

• The chronically progressive course of the disease may be punctuated by exacerbations.

• Disease progression should be regularly monitored by measuring the depth of the fornices and noting the position of adhesions.

3 Cornea

• Epithelial defects associated with drying and exposure (Fig. 5.19A).

• Infiltration and peripheral vascularization (Fig. 5.19B).

• Keratinization and ‘conjunctivalization’ of the corneal surface following damage to the limbus and consequent epithelial stem cell failure (Fig. 5.19C).

• End-stage disease is characterized by total symblepharon and corneal opacification (Fig. 5.19D).

4 Eyelids

• Aberrant (dysplastic) lashes, chronic blepharitis and keratinization of the lid margin.

• Ankyloblepharon, in which there are adhesions at the outer canthus between the upper and lower lids.

Fig. 5.18 Conjunctivitis in ocular cicatricial pemphigoid. (A) Hyperaemia, chemosis and necrosis; (B) subretinal fibrosis and forniceal shortening; (C) flat plica and keratinized caruncle; (D) a symblepharon

(Courtesy of S Tuft)

Fig. 5.19 Keratopathy in ocular cicatricial pemphigoid. (A) Epithelial defect; (B) peripheral vascularization and infiltration; (C) keratinization and ankyloblepharon; (D) end-stage disease

(Courtesy of S Tuft)

Systemic features

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1 Mucosal involvement is very common and is characterized by subepidermal blisters, most frequently oral (Fig. 5.20A). The blisters rupture within a day or two leaving erosions and ulcers that heal without significant scarring. Ulcers in other sites typically heal with scarring which may result in stricture formation. Stricture of the oesophagus can result in regurgitation and aspiration of food. Laryngeal or tracheal stenosis may be life-threatening.

2 Skin lesions are less common (25%) and present as tense blisters and erosions. They may involve the head and neck (Fig. 5.20B), the groins and extremities (Fig. 5.20C) but generalized involvement is uncommon (Fig. 5.20D).

Fig. 5.20 Mucous membrane pemphigoid. (A) Oral blisters; (B) mild involvement of the neck; (C) severe involvement of the leg; (D) generalized disease

(Courtesy of S Tuft – figs A and B)

Systemic treatment

1 Dapsone is a useful first-line treatment in patients with mild–moderate disease, at a dose of 1 mg/kg daily increasing to 100 mg or 200 mg, if tolerated; approximately 70% of patients respond. The drug is contraindicated in glucose-6-phosphate dehydrogenase deficiency.

2 Antimetabolites such as azathioprine, methotrexate or mycophenolate mofetil (CellCept®) are alternatives for mild–moderate disease if dapsone is contraindicated, ineffective or poorly tolerated, and are suitable for long-term therapy. Antimetabolites can be used in conjunction with dapsone if necessary, although only if the latter has shown a degree of efficacy.

3 Steroids (oral prednisolone 1–1.5 mg/kg) are effective for rapid disease control, but adverse effects virtually preclude the long-term use of higher doses.

4 Other measures

• Intravenous immunoglobulin therapy has shown promising results in some patients unresponsive to other agents.

• Ciclosporin has been used with apparent benefit although data to support its effect are limited.

Local treatment

1 Topical

• Artificial tears are an integral part of most regimens.

• Steroids as adjunctive treatment.

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• Retinoic acid may reduce keratinization.

• Antibiotics when indicated.

• Lid hygiene and low-dose oral tetracycline for blepharitis.

2 Subconjunctival mitomycin-C and/or steroid injection may be used as a temporizing aid or if systemic immunosuppression is not possible.

3 Contact lenses may be used with caution to protect the cornea from aberrant lashes and from dehydration.

Reconstructive surgery

Reconstructive surgery, preferably under systemic steroid cover, should be considered when active disease is controlled.

• Aberrant eye lashes can be treated by laser ablation or cryotherapy; the latter may be combined with lid splitting to expose the follicles.

• Severe dry eyes may be helped by punctal occlusion, if not already ablated by scarring.

• Promotion of healing of persistent or recurrent corneal epithelial defects by lateral tarsorrhaphy or botulinum toxin-induced ptosis.

• Entropion is best managed by a procedure (e.g. retractor plication) that does not involve conjunctival incision.

• Conjunctival keratinization may be addressed by mucous membrane autografting (e.g. oral) or amniotic membrane transplantation; these techniques can also be used for forniceal restoration.

• Limbal stem cell transfer may be attempted for corneal epithelialization failure.

• Keratoplasty carries a high risk of failure due to surface morbidity; lamellar grafts may be effective for perforations.

• Keratoprostheses may be the only option in end-stage disease.

Stevens–Johnson syndrome/toxic epidermal necrolysis (Lyell syndrome)

Definition

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Previously, the terms ‘Stevens–Johnson syndrome (SJS)’ and ‘erythema multiforme major’ were often used synonymously. However, it is now believed that erythema multiforme (without the ‘major’) is a distinct disease, milder and recurrent, with somewhat dissimilar clinical features and a tendency for different precipitating factors (erythema multiforme predominantly infections, Stevens–Johnson predominantly drugs). ‘Toxic epidermal necrolysis’ (TEN – Lyell syndrome) is a severe variant of SJS. Classically, SJS/TEN patients tend to be young adults, though other age groups, including children and the elderly, may be affected. An SJS-type presentation is more common in males than females, with the reverse probably true for TEN.

Pathogenesis

It is thought that a cell-mediated delayed hypersensitivity immune reaction is involved, either directly to drugs or to epithelial cell antigens modified by drug exposure. A wide range of drugs have been incriminated including antibiotics (especially sulfonamides and trimethoprim), analgesics, cough and cold remedies, cocaine, non-steroidal anti-inflammatory agents, anticonvulsants and allopurinol.

Micro-organisms include Mycoplasma pneumoniae and herpes simplex virus (HSV). Because symptoms often take 3 weeks to develop after exposure, in over 50% of cases the precipitating cause cannot be identified with certainty. Particular HLA alleles have been linked to a greater likelihood of developing SJS/TEN on exposure to particular drug groups.

Ocular features

1 Presentation is with flu-like symptoms which may last up to 14 days before the appearance of mucocutaneous lesions.

2 Acute signs

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• Haemorrhagic crusting of the lid margins that may become substantially confluent (Fig. 5.21A).

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• Papillary conjunctivitis, which can range from mild, transient and self-limiting to severe.

• Conjunctival membranes and pseudomembranes (Fig. 5.21B), severe hyperaemia, haemorrhages, blisters and patchy infarction.

• Keratopathy manifests a spectrum from punctate erosions to larger epithelial defects, secondary bacterial keratitis and occasionally perforation.

3 Late signs

• Keratinization of the conjunctiva and lid margin (Fig. 5.21C), sometimes with abrasive plaque formation.

• Posterior lid margin disease with opening of meibomian gland orifices onto the lid surface (Fig. 5.21D).

• Forniceal shortening and symblepharon formation.

• Eyelid complications include cicatricial entropion and ectropion, trichiasis, metaplastic lashes (Fig. 5.21E) and ankyloblepharon.

• Keratopathy including scarring, vascularization and keratinization (Fig. 5.21F) as a result of the primary inflammation and/or infection, as well as cicatricial entropion and aberrant lashes.

• Watery eyes due to fibrosis of the lacrimal puncta. Dry eyes may also occur as a result of fibrosis of lacrimal gland ductules and conjunctival metaplasia with loss of goblet cells.

Fig. 5.21 Ocular features in Stevens–Johnson syndrome. (A) Acute conjunctivitis and haemorrhagic lid crusting; (B) pseudomembrane formation; (C) conjunctival keratinization; (D) keratinization and severe posterior lid margin disease; (E) metaplastic lashes; (F) corneal keratinization

(Courtesy of S Tuft – figs D and F)

Systemic features

1 Mucosal involvement is characterized by blistering and haemorrhagic crusting of the lips (Fig. 5.22A). The blisters may also involve the tongue, oropharynx, nasal mucosa and occasionally the genitalia.

2 Skin

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• Small purpuric, vesicular or necrotic lesions involving the extremities, face and trunk (Fig. 5.22B). These are usually transient but may be widespread. Healing usually occurs within 1–4 weeks, leaving a pigmented scar.

• Widespread sloughing of the epidermis (Fig. 5.22C) is uncommon.

3 ‘Target’ lesions showing the classic three zones (Fig. 5.22D) are now viewed as characteristic of erythema multiforme rather than SJS/TEN, but the mucosal lesions appear similar in both conditions.

Fig. 5.22 Systemic features in Stevens–Johnson syndrome. (A) Haemorrhagic lip crusting; (B) extensive purpuric lesions; (C) epidermal sloughing; (D) ‘target’ lesion of erythema multiforme

(Courtesy of M Zatouroff, from Physical Signs in General Medicine, Mosby-Wolfe 1996 – fig. C)

Systemic treatment

1 Removal of the precipitant if possible, such as discontinuation of drugs and treatment of suspected infection.

2 General supportive measures such as maintenance of adequate hydration, electrolyte balance and nutrition (especially protein replacement) are critical. Management in a specialist burns unit should reduce the chance of infection when the extent of skin involvement is substantial.

3 Systemic steroids remain controversial. There are reports of increased mortality in older papers, but later research has raised the possibility that early high-dose intravenous treatment may improve outcomes.

4 Other immunosuppressants including ciclosporin, azathioprine, cyclophosphamide and intravenous immunoglobulin may be considered in selected cases, but are controversial and controlled trials are lacking.

5 Systemic antibiotics may be given as prophylaxis against skin or other systemic infection, avoiding those known to be at higher risk of precipitating SJS/TEN.

Ocular treatment

1 Acute disease

• Topical lubricants are used as frequently as necessary.

• Topical steroids may be used but their efficacy has not been demonstrated conclusively.

• Lysis of developing symblephara with a sterile glass rod or damp cotton bud.

• A scleral ring, consisting of a large haptic lens with the central zone removed, may help to prevent symblepharon formation (Fig. 5.23A).

• Pseudomembrane/membrane peeling (Fig. 5.23B) can be considered although the benefit is unproven.

• Treatment of acute corneal problems such as bacterial keratitis.

2 Chronic disease management addressing complications.

• Adequate lubrication, including punctal occlusion if necessary.

• Topical transretinoic acid 0.01% or 0.025% may reverse keratinization.

• Treatment of aberrant lashes.

• Bandage contact lenses (typically gas permeable scleral lenses – Fig. 5.24C) to maintain surface moisture, protect the cornea from aberrant lashes, and address irregular astigmatism.

• Mucous membrane grafting (e.g. buccal mucosa autograft) for forniceal reconstruction.

3 Corneal rehabilitation may involve the following:

• Superficial keratectomy for keratinization.

• In eyes with reasonable stem cell function, lamellar corneal grafting may be used for superficial scarring and is generally preferred to penetrating keratoplasty.

• Amniotic membrane grafting.

• Limbal stem cell transplantation (cadaveric or living relative).

• Keratoprosthesis implantation in end-stage disease.

Fig. 5.23 Treatment of Stevens–Johnson syndrome. (A) Scleral ring in place; (B) peeling of membrane; (C) bandage contact lens; (D) keratoprosthesis

(Courtesy of S Tuft – figs A and C; J Dart – fig. B; E Wylegala – fig D)

Fig. 5.24 Superior limbic keratoconjunctivitis. (A) Papillary hypertrophy; (B) bulbar conjunctival injection and limbal papillae; (C) redundant conjunctiva; (D) superior corneal filaments

(Courtesy of S Tuft – fig. C; C Barry – fig. D)

Miscellaneous conjunctivitis

Superior limbic keratoconjunctivitis

Definition

Superior limbic keratoconjunctivitis (SLK) is an uncommon chronic disease of the superior limbus and the superior bulbar and tarsal conjunctiva. It typically affects both eyes of middle-aged women, approximately 50% of whom have abnormal thyroid function (usually hyperthyroidism); approximately 3% of patients with thyroid eye disease have SLK. The condition is probably under-diagnosed because symptoms are typically more severe than signs. The course can be prolonged over years although remission eventually occurs spontaneously. There are similarities to mechanically-induced papillary conjunctivitis, and a comparable clinical picture has been described with contact lens wear and following upper lid surgery or trauma.

Pathogenesis

SLK is believed to be the result of blink-related trauma between the upper lid and the superior bulbar conjunctiva, precipitated in many cases by tear film insufficiency and an excess of lax conjunctival tissue. With increased conjunctival movement there is mechanical damage to the tarsal and bulbar conjunctival surfaces, the resultant inflammatory response leading to increasing conjunctival oedema and redundancy, with the creation of a self-perpetuating cycle.

Diagnosis

1 Presentation is with non-specific symptoms, often intermittent, such as foreign body sensation, burning, mild photophobia, mucoid discharge and frequent blinking.

2 Conjunctiva

• Papillary hypertrophy of the superior tarsus, often having a diffuse velvety appearance (Fig. 5.24A).

• Hyperaemia of a radial band of the superior bulbar conjunctiva and limbal papillary hypertrophy (Fig. 5.24B).

• Light downward pressure on the upper lid results in a fold of redundant conjunctiva crossing the upper limbus (Fig. 5.24C).

• Petechial haemorrhages may be present.

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3 Cornea

• Superior punctate corneal epithelial erosions are common and are often separated from the limbus by a zone of normal epithelium.

• Superior filamentary keratitis (Fig. 5.24D) develops in about one-third of cases.

• Mild superior pannus resembling arcus senilis may develop in long-standing disease.

4 Keratoconjunctivitis sicca is present in only about 50% of cases.

5 Thyroid function testing should be performed if the patient is not already known to have thyroid dysfunction.

Treatment

Conservative measures should be tried initially.

1 Topical

a Lubricants to reduce friction between the tarsal and bulbar conjunctiva should be used regularly and frequently.

b Acetylcysteine 5% or 10% q.i.d. to break down filaments and provide lubrication.

c Mast cell stabilizers and steroids address any inflammatory component; steroids may be best used in short intensive courses with rapid tapering, and should be reserved for severe cases.

d Ciclosporin 0.05% b.d. as primary or adjunctive therapy, particularly in the presence of coexisting keratoconjunctivitis sicca.

e Retinoic acid to retard keratinization.

f Autologous serum 20% drops can be beneficial but may require instillation up to 10 times a day.

2 Soft contact lenses, which intervene between the lid and the superior conjunctiva, are effective in some cases. Interestingly, a unilateral lens may provide bilateral relief.

3 Supratarsal steroid injection. 0.1 mL of triamcinolone 40 mg/mL to break the inflammatory cycle.

4 Temporary superior and/or inferior punctal occlusion using a plug.

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5 Resection of the superior limbal conjunctiva, either in a zone extending 2 mm from the superior limbus or of the area staining with rose bengal, is often effective in resistant disease. Lax conjunctiva is removed, with regrowth tending to be firmly anchored.

6 Conjunctival ablation by applying silver nitrate 0.5% (not cautery sticks) or thermocautery to the affected area.

7 Treatment of associated thyroid dysfunction may improve SLK.

Ligneous conjunctivitis

Definition

Ligneous conjunctivitis is a very rare disorder characterized by recurrent, often bilateral fibrin-rich pseudomembranous lesions of wood-like consistency that develop mainly on the tarsal conjunctiva. It is generally a systemic condition which may involve the periodontal tissue, the upper and lower respiratory tract, kidneys, middle ear and female genitalia. It can be sight-threatening, and death can occasionally occur from pulmonary involvement.

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Pathogenesis

It is thought that in susceptible patients patterns of damage repair are abnormal, notably a failure of normal clearance of products of the acute stages of the healing process. A deficiency in plasmin-mediated fibrinolysis may be a key common factor in many patients. Episodes may be triggered by relatively minor trauma, or by systemic events such as fever and antifibrinolytic therapy. Histology shows amorphous subepithelial deposits of eosinophilic material consisting predominantly of fibrin (Fig. 5.25A).

Fig. 5.25 Ligneous conjunctivitis. (A) Histology shows eosinophilic fibrinous coagulum on the conjunctival surface; (B) multiple ligneous lesions; (C) thick overlying mucus; (D) end-stage disease with corneal destruction

(Courtesy of J Harry and G Misson, from Clinical Ophthalmic Pathology, Butterworth-Heinemann, 2001 – fig. A; JH Krachmer, MJ Mannis and EJ Holland, from Cornea, Mosby 2005 – figs B and D; R Fogla – fig. C)

Diagnosis

1 Presentation is with nonspecific conjunctivitis, usually in childhood (median age 5 years), although onset may be at any age. A conjunctival lesion is commonly noted by parents.

2 Signs

• Red-white lobular conjunctival masses (Fig. 5.25B).

• The lesions may be covered by a yellow-white thick mucoid discharge (Fig. 5.25C).

• Corneal scarring, vascularization, infection or melting in advanced disease (Fig. 5.25D).

Treatment

Treatment tends to be unsatisfactory and spontaneous resolution is rare. It is important to discontinue any antifibrinolytic drugs.

1 Surgical removal with meticulous diathermy of the base of the lesion. Pre-operative topical plasminogen may soften pseudomembranes and facilitate removal.

2 Topical

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• Following membrane removal, hourly heparin and steroids are commenced immediately and continued until the wound has re-epithelialized, with subsequent tapering over several weeks until all signs of inflammation have disappeared.

• Recurrence may be retarded by long-term ciclosporin and steroid instillation.

3 Other modalities

• Intravenous or topical plasminogen.

• Amniotic membrane transplantation to the conjunctiva following lesion removal.

Parinaud oculoglandular syndrome

Parinaud oculoglandular syndrome or conjunctivitis is a rare condition consisting of chronic low-grade fever, unilateral granulomatous conjunctivitis with surrounding follicles (Fig. 5.26) and ipsilateral regional (preauricular) lymphadenopathy. It is virtually synonymous with cat-scratch disease (caused by Bartonella henselae), although several other causes have been implicated, including tularaemia, insect hairs (ophthalmia nodosum), T. pallidum, sporotrichosis, tuberculosis, and acute Chlamydia trachomatis infection.

Fig. 5.26 Granulomatous conjunctivitis in Parinaud syndrome

Factitious conjunctivitis

Self-injury (factitious keratoconjunctivitis) is most often intentional although can also occur inadvertently, as in mucous fishing syndrome and removal of contact lenses. Damage may be the result of either mechanical abrasion or perforation, or of the instillation of irritant but readily accessible household substances, such as soap. Occasionally over-instillation of prescribed ocular medication is responsible.

Diagnosis

• Inferior conjunctival injection and staining with rose bengal (Fig. 5.27), with a quiet superior bulbar conjunctiva.

• Linear corneal abrasions, persistent epithelial defects and occasionally focal corneal perforation.

• Secondary infection with Candida spp.

• Sterile ring infiltrate and hypopyon.

• Corneal scarring.

• The patient may have sought multiple medical opinions over an extended period, often from a range of specialists for different systemic complaints.

• Reported symptoms may seem disproportionate to signs.

Fig. 5.27 Inferior conjunctival injection and staining with rose bengal in factitious conjunctivitis

(Courtesy of S Tuft)

Management

• Exclude other diagnoses.

• Close observation may be required.

• Confrontation often leads to failure to return for review.

• A psychiatric opinion may be appropriate.

Degenerations

Pingueculum

A pingueculum is an extremely common, innocuous, usually bilateral and asymptomatic ‘elastotic’ degeneration of the collagen fibres of conjunctival stroma. The cause is believed to be actinic damage, similar to the aetiology of pterygium (see below).

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1 Signs. A yellow-white mound or aggregation of smaller mounds on the bulbar conjunctiva adjacent to the limbus. It is more frequently located at the nasal than the temporal limbus (Fig. 5.28A), although is frequently present at both. Calcification is occasionally visible.

2 Treatment is usually unnecessary because growth is very slow or absent. Occasionally, however, a pingueculum may become acutely inflamed (pingueculitis – Fig. 5.28B) and require a short course of a weak steroid such as fluorometholone. Excision is occasionally performed for cosmetic reasons or if a large lesion is causing significant irritation.

Fig. 5.28 (A) Pingueculum; (B) pingueculitis

Pterygium

A pterygium is a triangular fibrovascular subepithelial ingrowth of degenerative bulbar conjunctival tissue over the limbus onto the cornea. It typically develops in patients who have been living in hot climates and, as with pinguecula, may represent a response to ultraviolet exposure and possibly to other factors such as chronic surface dryness. A pterygium is histologically similar to a pingueculum and shows elastotic degenerative changes in vascularized subepithelial stromal collagen (Fig. 5.29A).

Fig. 5.29 Pterygium. (A) Histology shows collagenous degenerative changes in vascularized subepithelial stroma; (B) type 1; (C) type 2; (D) type 3; (E) pseudopterygium caused by a chemical burn

(Courtesy of J Harry – fig. A)

Clinical features

1 Symptoms

• Many small lesions are asymptomatic.

• Irritation and grittiness caused by a dellen effect at the advancing edge due to interference with the precorneal tear film (more likely if the head of the pterygium is especially elevated).

• Patients who wear contact lenses may develop symptoms of irritation at an earlier stage due to edge lift.

• Interference with vision by obscuring the visual axis or inducing astigmatism.

• Intermittent inflammation similar to pingueculitis.

• Cosmesis may be a significant problem.

• If pseudopterygium is suspected, there may be a history of a causative episode.

2 Signs. A pterygium is made up of three parts: a ‘cap’ (an avascular halo-like zone at the advancing edge), a head, and a body.

a Type 1 extends less than 2 mm onto the cornea (Fig. 5.29B). A deposit of iron (Stocker line) may be seen in the corneal epithelium anterior to the advancing head of the pterygium.

b Type 2 involves up to 4 mm of the cornea and may be primary or recurrent following surgery (Fig. 5.29C).

c Type 3 encroaches onto more than 4 mm of the cornea and involves the visual axis (Fig. 5.29D).

d Pseudopterygium is caused by a band of conjunctiva adhering to an area of compromised cornea at its apex. It forms as a response to an acute inflammatory episode such as a chemical burn (Fig. 5.29E), corneal ulcer (especially if marginal), trauma and cicatrizing conjunctivitis.

Treatment

1 Medical treatment of symptomatic patients involves tear substitutes, and topical steroids for inflammation. The patient may also be advised to wear sunglasses to reduce ultraviolet exposure and decrease the growth stimulus.

2 Surgical technique. Simple excision (‘bare sclera’ technique) is associated with a high rate of recurrence (around 80%) that may be more aggressive than the initial lesion.

• Simple conjunctival flap.

• Conjunctival autografting, currently the most popular approach. The donor conjunctival patch is usually harvested from the superior paralimbal region – the site usually heals well.

• Adjunctive treatment with mitomycin C or beta-irradiation; may rarely be complicated by late scleral necrosis (see Fig. 8.9C).

• Amniotic membrane patch grafting (may be reserved for more aggressive lesions or recurrences).

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• Occasionally peripheral lamellar keratoplasty is required for deep lesions.

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Concretions

Concretions are extremely common and are usually associated with aging, although they can also form in patients with chronic conjunctival inflammation such as trachoma.

1 Signs

• Multiple tiny cysts containing yellowish-white deposits of epithelial debris including keratin, usually located subepithelially in the inferior tarsal and forniceal conjunctiva (Fig. 5.30A).

• Can become calcified and, particularly if large, may erode the overlying epithelium (Fig. 5.30B) and cause irritation.

2 Treatment of symptomatic concretions involves removal at the slit-lamp with a needle under topical anaesthesia.

Fig. 5.30 (A) Multiple small concretions; (B) large concretion eroding the conjunctival surface

Conjunctivochalasis

Conjunctivochalasis is probably a normal ageing change that may be exacerbated by posterior lid margin disease. Mechanical stress on the conjunctiva precipitated by dry eye is a potential initiating mechanism.

1 Symptoms

• Watering of the eye by mechanical obstruction of the inferior punctum and interference with the marginal tear meniscus.

• Foreign body sensation on downgaze.

2 Signs

• A fold of redundant conjunctiva interposed between the globe and lower eyelid protrudes over the lid margin.

• Inferior conjunctival and corneal staining with rose bengal (Fig. 5.31).

3 Treatment

• Topical lubricants and treatment of blepharitis (e.g. oral doxycycline).

• A short course of topical steroids or other anti-inflammatory agent may be helpful.

• Conjunctival resection can be performed in severe cases.

Fig. 5.31 Conjunctivochalasis stained with rose bengal

(Courtesy of S Tuft)

Retention (epithelial inclusion) cyst

1 Histology shows a fluid-filled internal cavity lined by a double epithelial layer.

2 Signs. Thin-walled lesion containing clear (Fig. 5.32A) or occasionally turbid fluid (Fig. 5.32B). The cyst does not usually cause discomfort but may be a mild cosmetic blemish.

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3 Treatment, if required, is by simple puncture with a needle. It is important to approach the cyst with the needle tangential rather than perpendicular to the globe. Bleeding should be encouraged within the ruptured cyst as it may encourage adhesion of the walls and reduce the chance of recurrence. Cyst wall excision under topical anaesthesia can be carried out if puncture fails.

4 Differential diagnosis includes secondary inclusion cyst that may develop following strabismus surgery, and lymphangiectasia. The latter is characterized by strings of cystic or sausage-shaped clear-walled channels that may become filled with blood (haemorrhagic lymphangiectasia – Fig. 5.33).

Fig. 5.32 (A) Retention cysts with clear fluid; (B) retention cyst with turbid fluid

(Courtesy of R Tompkin – fig. B)

Fig. 5.33 Haemorrhagic lymphangiectasia

(Courtesy of R Bates)