Simple episcleritis

Simple episcleritis accounts for three-quarters of all cases and predominantly affects females. It has a great tendency to recur either in the same eye, or sometimes both together. The attacks become less frequent and after many years disappear completely.

Fig. 8.2 Simple episcleritis. (A) Sectoral; (B) diffuse

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

Nodular episcleritis

Nodular episcleritis also tends to affect young females but has a less acute onset and a more prolonged course than the simple variety.

Fig. 8.3 (A) Nodular episcleritis; (B) slit-lamp examination shows that the deep beam is not displaced above the scleral surface

Anterior non-necrotizing scleritis

Diffuse

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Diffuse disease is slightly more common in females and usually presents in the 5th decade.

1 Presentation is usually with ocular redness followed a few days later by aching and pain which may spread to the face and temple. The pain typically wakes the patient in the early hours of the morning and improves later in the day; it responds poorly to common analgesics.

2 Signs

• Vascular congestion and dilatation associated with oedema. If treatment is started early, which rarely happens, the disease can be completely inhibited.

The redness may be generalized (Fig. 8.4A) or localized to one quadrant. If confined to the areas under the upper eyelid the diagnosis may be missed if the eyelid is not elevated.

• As the oedema resolves, the affected area often takes on a slight grey/blue appearance because of increased scleral translucency; this is due to rearrangement of scleral fibres rather than a decrease in scleral thickness (Fig. 8.4B).

• Recurrences at the same location are common unless the underlying cause is treated.

• The duration of disease is approximately 6 years and the frequency of recurrences decreases after the first 18 months. The long-term visual prognosis is very good.

Fig. 8.4 (A) Diffuse non-necrotizing anterior scleritis; (B) scleral translucency following recurrent disease

(Courtesy of M Jager – fig. B)

Nodular

The incidence of nodular and diffuse anterior scleritis is the same but a disproportionately large number of those with nodular disease have had a previous attack of herpes zoster ophthalmicus. The age of onset is similar to that of diffuse scleritis.

1 Presentation is with the insidious onset of pain followed by increasing redness, tenderness of the globe and the appearance of a scleral nodule.

2 Signs

• Scleral nodules may be single (Fig. 8.5A) or multiple and most frequently develop in the interpalpebral region 3–4 mm away from the limbus. They have a deeper blue-red colour than episcleral nodules and are immobile.

• Slit-lamp examination shows that the slit beam is displaced by the scleral nodule (Fig. 8.5B).

• Instillation of 2.5% phenylephrine drops will constrict the conjunctival and superficial episcleral vasculature but not the deep plexus over the nodule.

• Multiple nodules may coalesce, become confluent, expanding sometimes to an enormous size if treatment is delayed.

• As the inflammation in the nodule subsides, increased translucency of the sclera becomes apparent.

• The duration of the disease is similar to diffuse scleritis.

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• Over 10% of patients with nodular scleritis develop necrotizing disease but if treatment is instituted early superficial necrosis does not occur and the nodule heals from the centre leaving a small atrophic scar.

Fig. 8.5 (A) Nodular non-necrotizing anterior scleritis; (B) slit-lamp examination shows displacement of the entire beam

Anterior necrotizing scleritis with inflammation

Necrotizing disease is the aggressive form of scleritis. The age at onset is later than that of non-necrotizing scleritis, averaging 60 years. The condition is bilateral in 60% of patients and unless appropriately treated, especially in its early stages, it may result in severe visual morbidity and sometimes loss of the eye.

Clinical features

1 Presentation is with gradual onset of pain which becomes severe and persistent and radiates to the temple, brow or jaw; it frequently interferes with sleep and responds poorly to analgesia.

2 Signs vary according to the following three types of necrotizing disease as follows:

a Vaso-occlusive is often associated with rheumatoid arthritis.

• Isolated patches of scleral oedema with overlying non-perfused episclera and conjunctiva.

• The patches coalesce, and if unchecked rapidly proceed to progressive scleral necrosis (Fig. 8.6A and B).

b Granulomatous is often associated with Wegener granulomatosis and polyarteritis nodosa.

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• The disease typically starts with injection adjacent to the limbus and then extends posteriorly.

• Within 24 hours, the sclera, episclera, conjunctiva and adjacent cornea become irregularly raised and oedematous (Fig. 8.7).

c Surgically-induced scleritis typically starts within 3 weeks of the surgical procedure, but much longer intervals have been reported.

• Scleritis may be induced by any type of surgery including strabismus repair, trabeculectomy (Fig. 8.8A) and scleral buckling (Fig. 8.8B), and treatment of pterygium with adjunctive mitomycin C (Fig. 8.8C).

• The necrotizing process starts at the site of surgery and then extends outwards but, unlike other forms of necrotizing disease, it tends to remain localized to one segment.

Fig. 8.6 Vaso-occlusive necrotizing scleritis with inflammation. (A) Early stage; (B) advanced disease

Fig. 8.7 Granulomatous necrotizing scleritis with inflammation

(Courtesy of P Watson)

Fig. 8.8 Surgically-induced necrotizing scleritis. (A) Following trabeculectomy; (B) following scleral buckling; (C) following use of mitomycin C in the treatment of pterygium

(Courtesy of R Fogla – fig. C)

Complications

1 Acute infiltrative stromal keratitis may be localized or diffuse.

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2 Sclerosing keratitis, characterized by chronic thinning and opacification in which the peripheral cornea adjacent to the site of scleritis resembles sclera (see Fig. 6.31D).

3 Peripheral ulcerative keratitis is characterized by progressive melting and ulceration which may eventually be more serious than the scleritis (Fig. 8.9). In granulomatous scleritis the destruction extends directly from the sclera into the limbus and cornea. This characteristic pattern is seen in Wegener granulomatosis, polyarteritis nodosa and relapsing polychondritis. Peripheral corneal ulceration can occur at any stage of a necrotizing scleritis and, in rare cases, precede its onset.

4 Uveitis, if severe, usually denotes aggressive scleritis.

5 Glaucoma is the most common cause of eventual loss of vision. The intraocular pressure is very difficult to control in the presence of active scleritis.

6 Hypotony may be the result of ciliary body detachment, inflammatory damage or ischaemia.

7 Perforation of the sclera as a result of the inflammatory process alone is extremely rare.

Fig. 8.9 Peripheral ulcerative keratitis secondary to necrotizing scleritis

Scleromalacia perforans

Scleromalacia perforans is a specific type of necrotizing scleritis without inflammation that typically affects elderly women with longstanding rheumatoid arthritis. The use of the word ‘perforans’ is unfortunate because perforation of the globe is extremely rare as the integrity of the globe is maintained by a thin, but complete, layer of fibrous tissue.

Fig. 8.10 Progression of scleromalacia perforans. (A) Asymptomatic necrotic patch; (B) thinning and exposure of underlying uvea

(Courtesy of R Bates – fig. A; C Barry – fig. B)

Posterior scleritis

Posterior scleritis is a serious, potentially blinding condition, which is often misdiagnosed and treated very late. The age at onset is often under the age of 40 years. The disease is bilateral in 35% of cases. It is important to remember that the inflammatory changes seen in posterior and anterior scleral disease are identical and can arise in both segments simultaneously or separately. The presence of anterior scleritis is a great help if posterior scleritis is suspected but it only occurs in a minority of cases. Patients with posterior scleritis can go blind extremely rapidly, so correct, early diagnosis is crucial. Young patients are usually healthy but about a third of those over the age of 55 years have associated systemic disease.

Diagnosis

1 Presentation may be with discomfort or pain. Surprisingly pain does not correlate to the severity of orbital inflammation but tends to be more severe in those with accompanying orbital myositis. Tenderness to palpation is very common but photophobia is not a dominant feature.

2 Signs

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a Exudative retinal detachment occurs in almost 25% of cases (see Fig. 16.59).

b Uveal effusion characterized by exudative retinal detachment and choroidal detachment (Fig. 8.11A).

c Choroidal folds represent an anterior displacement of the choroid. They are usually confined to the posterior pole and run horizontally (Fig. 8.11B).

d Subretinal mass characterized by a yellowish-brown elevation which may be mistaken for a choroidal tumour.

e Disc oedema with an accompanying slight reduction of vision is common. It is caused by spread of the granulomatous process into the orbital tissue and the optic nerve. Treatment must not be delayed in these patients as vision can be lost rapidly due to ischaemia.

f Myositis is common and gives rise to diplopia, pain on eye movement, tenderness to touch and redness around a muscle insertion.

g Proptosis is usually mild and frequently associated with ptosis.

h Other features occasionally present include glaucoma, periorbital oedema, chemosis and conjunctival injection.

3 Ultrasound is extremely useful in showing increased scleral thickness, scleral nodules and separation of Tenon capsule from the sclera. Fluid in Tenon’s space gives rise to the characteristic ‘T’ sign in which the stem of the T is formed by the optic nerve on its side and the cross bar by the gap containing fluid (Fig. 8.12A). Ultrasonography will also show disc oedema, choroidal folds or retinal detachment.

4 MR and CT (Fig. 8.12B) may show scleral thickening and proptosis.

Fig. 8.11 Signs of posterior scleritis. (A) Uveal effusion; (B) choroidal folds

Fig. 8.12 Special investigations in posterior scleritis. (A) B-scan shows scleral thickening and fluid in sub-Tenon space; (B) axial CT shows right scleral thickening and proptosis

Important systemic associations of scleritis

Rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune systemic disease characterized by a symmetrical, destructive, deforming, inflammatory polyarthropathy, in association with a spectrum of extra-articular manifestations and circulating antiglobulin antibodies, termed rheumatoid factor. It is much more common in females than males.

1 Presentation is often in the 3rd decade with joint swelling, usually of the hands.

2 Signs

• Symmetrical arthritis of the small joints of the hands typically involving the proximal interphalangeal and spares the distal interphalangeal joints.

• Joint instability may result in subluxation and deformities (Fig. 8.13A), such as ulnar deviation of the metacarpophalangeal joints.

• Less frequent involvement of the feet, shoulders, elbows, hips and cervical spine.

• Skin involvement includes subcutaneous nodules over bony prominences, and vasculitis which may cause ulceration.

3 Complications include pulmonary nodules and fibrosis, multifocal neuropathy, septic arthritis, secondary amyloidosis and carpal tunnel syndrome.

4 Scleritis. RA is by far the most common systemic association of scleritis. Patients with non-necrotizing scleritis usually have mild joint disease whereas necrotizing disease tends to affect patients with severe long-standing rheumatoid disease with extra-articular manifestations, most notably rheumatoid nodules.

5 Other ocular manifestations include KCS (secondary Sjögren syndrome), ulcerative keratitis and acquired superior oblique tendon sheath syndrome (very rare).

Fig. 8.13 Important systemic associations of scleritis. (A) Severe deformities of the hands in rheumatoid arthritis; (B) CT shows lung cavitation in Wegener granulomatosis; (C) saddle-shaped nasal deformity in relapsing polychondritis; (D) purpura in polyarteritis nodosa

(Courtesy of M Zatouroff, from Physical Signs in General Medicine, Mosby 1996 – fig. A; JA Nerad, KD Carter and MA Alford, from Oculoplastic and Reconstructive Surgery, in Rapid Diagnosis in Ophthalmology, Mosby 2008 – fig. B; C Pavésio – fig. C)

Treatment of immune-mediated scleritis

Alkaptonuria

Fig. 8.15 Alkaptonuria. (A) Histology of scleral ochronosis; (B) dark urine with normal for comparison; (C) spinal disc degeneration; (D) pigmentation of the sclera and horizontal rectus tendons associated with pigment globules

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

Haemochromatosis

Osteogenesis imperfecta

Osteogenesis imperfecta is an inherited disease of connective tissue, usually caused by defects in the synthesis and structure of Type 1 collagen. There are multiple types, at least two of which have ocular features.

Type I

1 Inheritance is AD.

2 Systemic features include few fractures with little or no deformity, hyperextensible joints, dental hypoplasia (Fig. 8.17A), deafness and easy bruising.

3 Ocular manifestations include blue sclera, megalocornea and corneal arcus.

Fig. 8.17 Osteogenesis imperfecta. (A) Dental hypoplasia; (B) multiple fractures in type IIA

(Courtesy of BJ Zitelli and HW Davis, from Atlas of Pediatric Physical Diagnosis, Mosby 2002 – fig. B)

Ehlers–Danlos syndrome type VI

Ehlers–Danlos syndrome VI (ocular sclerotic) is a rare, usually AR disorder of collagen caused by deficiency of procollagen lysyl hydroxylase. There are nine distinct subtypes but type 6 and, rarely, type 4, are associated with ocular features.

Fig. 8.18 Ehlers–Danlos syndrome type VI. (A) Cutaneous hyperelasticity; (B) papyraceous scarring; (C) joint hypermobility

(Courtesy of MA Mir, from Atlas of Clinical Diagnosis, Saunders, 2003 – figs A and B; JH Krachmer, MJ Mannis and EJ Holland, from Cornea, Elsevier 2005 – fig. C)

Other systemic associations

Congenital ocular melanocytosis

Classification

Congenital ocular melanocytosis is an uncommon condition characterized by an increase in number, size and pigmentation of melanocytes (Fig. 8.19A) in the sclera and uvea and may also involve the periocular skin, orbit, meninges and soft palate. It occurs in the following three clinical settings.

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1 Ocular melanocytosis, the least common, involves only the eye.

2 Dermal melanocytosis involves only the skin and accounts for about one-third of cases.

3 Oculodermal melanocytosis (naevus of Ota) is the most frequent type and involves both skin and eye.

Fig. 8.19 Congenital melanocytosis. (A) Histology shows an increase in the number, size and pigmentation of melonocytes in the inner sclera and choroid; (B) episcleral melanocytosis; (C) cutaneous melanocytosis

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

Ipsilateral associations

1 Iris hyperchromia is common (Fig. 8.20A).

2 Iris mammillations, which are tiny, regularly spaced, villiform lesions, are uncommon (Fig. 8.20B). They may also be found in patients with neurofibromatosis type 1, Axenfeld–Rieger anomaly and Peters anomaly.

3 Fundus hyperpigmentation can occur (Fig. 8.20C).

4 Trabecular hyperpigmentation (Fig. 8.20D) which is associated with glaucoma in about 10% of cases.

5 Uveal melanoma may develop in a small minority of patients, and long-term review is required.

Fig. 8.20 Ipsilateral associations of naevus of Ota. (A) Iris heterochromia; (B) iris mammillations; (C) fundus hyperpigmentation; (D) trabecular hyperpigmentation

(Courtesy of B Gilli – fig. A; L MacKeen – fig. D)

Idiopathic sclerochoroidal calcification

Idiopathic sclerochoroidal calcification is an innocuous, age-related condition that is usually bilateral.

Fig. 8.21 (A) Idiopathic sclerochoroidal calcification; (B) ultrasonogram shows a highly reflective lesion with orbital shadowing

(Courtesy of J Donald M Gass, from Stereoscopic Atlas of Macular Diseases, Mosby 1997 – fig. B)

Scleral hyaline plaque

Scleral hyaline plaques are bilateral oval, dark-greyish areas located close to the insertion of the horizontal rectus muscles (Fig. 8.22) that should not be confused with scleromalacia perforans. They typically affect elderly patients and are entirely innocuous.

Fig. 8.22 Scleral hyaline plaque