Scleritis

Episcleritis

Episcleritis is an inflammatory disorder involving the episcleral tissue that lies superficial to the sclera, just beneath the Tenon capsule. Although it occurs in both sexes and at all ages, it is seen more frequently in young to middle-aged women. Episcleritis is usually mild and is characterized by slight conjunctival injection and the presence of a foreign body sensation. The episodes often resolve without treatment, but episcleritis can recur. Occasionally, patients may experience more severe redness and pain. Inflamed episcleral blood vessels tend to have a salmon color in natural light, radiate from the limbus, and can be moved over the sclera with a cotton-tipped applicator. In addition, these more superficial vessels will blanch after administration of topical phenylephrine. Nodular episcleritis has also been described.

In 50% or greater of cases, episcleritis is idiopathic; however, many of the diseases associated with scleritis have also been associated with episcleritis. In a review of 100 patients with episcleritis, an associated systemic disease was found in 36 (36%). Although often self-limiting, episcleritis can be associated with corneal involvement, uveitis, and glaucoma.

Extensive evaluation for underlying disease may not be warranted for mild forms of the disease, especially if it is not recurrent. When treatment is required, the disease often responds to topical or oral nonsteroidal anti-inflammatory drugs (NSAIDs) or to topical corticosteroids. Although topical vasoconstrictors can reduce the redness, they should be used sparingly. In patients with episcleritis that fails to respond to initial therapy, one should suspect the possibility of a masquerade syndrome, such as a conjunctival malignancy or an underlying systemic disease.

The differential diagnosis of episcleritis includes conjunctivitis; a conjunctival malignancy, such as lymphoma; medications; and scleritis. Conjunctivitis, whether allergic or infectious, can frequently be distinguished from episcleritis on the basis of symptoms and examination findings. Infectious conjunctivitis is usually associated with a discharge and allergic conjunctivitis with itching and chemosis. Scleritis is anatomically deeper and has a distinct appearance. Malignant conjunctival lesions also tend to have a specific appearance and are rarely mistaken for episcleritis. A number of medications associated with both episcleritis and scleritis are listed in Box 21.1 .

The visual prognosis for patients with episcleritis is usually good. Some patients have a single episode, and in those with recurrent disease, the frequency of episodes tends to diminish over time. Because up to one-third of patients can have an associated systemic disease and because episcleritis can be associated with ocular complications, such as uveitis and glaucoma, patients with more severe or recurrent episcleritis should be carefully assessed and treated. Table 21.1 compares the features of episcleritis and scleritis.

Scleritis

The severity of scleritis varies greatly, but the disease can result in loss of vision and be difficult to treat. Scleritis is characterized by eye pain and redness of the sclera and episclera. The pain is usually gradual in onset but can become excruciating, with the feeling of something boring into the eye, and can wake the patient from sleep. The pain may radiate to the forehead or to other parts of the face and may be associated with photophobia and tearing. Corneal involvement, anterior uveitis, and exudative retinal detachments can occur and cause decreased vision. The inflamed sclera is deep to the episclera, typically with a violaceous hue, and the inflamed vessels cannot be moved with a cotton-tipped applicator ( Fig. 21.1 ). The disease is most common in the fourth to sixth decades of life and more common in women. Scleritis is bilateral in greater than 50% of patients, but it frequently starts in one eye. It can be divided into anterior and posterior diseases (see Table 21.1 ). Anterior scleritis has been classified into four additional categories ( Table 21.2 ): diffuse, nodular, necrotizing with inflammation, and necrotizing without inflammation. Necrotizing scleritis without inflammation is also called scleromalacia perforans. A standardized grading system for scleritis has been published and may be useful for clinical assessment and research purposes ( Fig. 21.2 ).

Necrotizing scleritis is a severe form of the disorder, frequently associated with both blinding ocular disease and life-threatening systemic disease. An underlying systemic disease was found in approximately one-half of patients with necrotizing scleritis. Necrotizing scleritis with inflammation is almost always painful. The sclera is edematous, and inflammation leads to scleral thinning, which allows the underlying choroid to become visible. Intraocular inflammation is often seen in severe cases of scleritis. Fluorescein angiography shows hypoperfusion or nonperfusion of the scleral vessels. Other complications of scleritis include cataract and glaucoma. In one review, an increase in intraocular pressure was noted in about one-fifth of patients.

Posterior scleritis is defined as inflammation of the sclera posterior to the ora serrata. Symptoms of posterior scleritis can be subtle, and the disease is frequently misdiagnosed. As with other forms of scleritis, pain is the most common symptom; however, vision is affected more frequently. Unlike other forms of scleritis, redness can be subtle and missed on examination. Other findings include retinal and/or choroidal folds, exudative retinal detachments, or choroidal masses. As with anterior scleritis, masquerade syndromes should be suspected in atypical cases of posterior scleritis, especially when the disease does not respond to treatment. Some of the malignant diseases masquerading as posterior scleritis include lymphoma, metastatic carcinoma, and choroidal melanoma. We have also seen occurrences of benign lymphoid hyperplasia involving the choroid and juvenile xanthogranuloma misdiagnosed as posterior scleritis. Nonmalignant disorders, including retinal detachments and central serous retinopathy, can also masquerade as posterior scleritis.

Scleritis occurs in children, although the characteristics of the disease can differ from those in adults. Episcleritis appears to occur less frequently in children but usually has a similar mild course as in adults. In a series of 24 eyes from 20 children with scleritis, the mean age at presentation was 12 years with equal sex distribution. The disease was unilateral in 80% of patients. Most eyes had posterior scleritis, and tuberculosis was the only associated systemic disease found in three (15%) patients. In a study of posterior scleritis in children, underlying systemic disease was also uncommon. Scleritis in children can occur after surgery, including strabismus surgery.