Episcleritis

are inevitably biased to higher numbers of patients with scleritis compared with patients with episcleritis, and to higher numbers of patients with episcleritis and scleritis with respect to the total number of new patient referrals. A signiÞcant factor in this is underreporting of episcleral disease. Objective data on the prevalence of episcleritis are very difÞcult to estimate because many patients with previously diagnosed episcleritis understand that recurrent episodes are unlikely to cause damage to the eye, so either they do not treat the condition or they self-medicate. The only ones who seek ophthalmological consultation (and usually not at a tertiary referral center) are those who are having their Þrst attack or who are overstressed. Objective data on the prevalence of scleritis are also difÞcult to obtain because they can vary greatly depending on the type of institution in which the studies are performed. Data from tertiary referral centers are inevitably biased to higher numbers of patients with scleritis with respect to the total number of new patient referrals. Examples of the prevalence variability depending on the type of institution are the following: of 9,600 new patient referrals to the Department of Ophthalmology of Southern General Hospital and Victoria InÞrmary in Glasgow during an 8-year period, 0.08% had scleritis [14]. Of 6,600 new patient referrals to the Immunology Service at the Massachusetts Eye and Ear InÞrmary Hospital in Boston during an 11-year period (May 1980 to May 1991), 2.6% had scleritis, and 1.4% had episcleritis [15]. Data from our current experience show higher numbers with respect to scleritis patients: of 4,909 new patient referrals to the MERSI in Cambridge

during a 5-year period (April 2005 to April 2010), 8.7% had scleritis and 1.4% had episcleritis.

Recognizing the bias of our two tertiary eye care centers, the prevalence of the different types of episcleritis and scleritis in our current series is shown in Table 4.1.

This chapter focuses on the clinical considerations of episcleritis and scleritis and their subcategories.

4.1Episcleritis

4.1.1Introduction

Episcleritis is a benign inßammatory disease that is characterized by edema and cellular inÞltration of the episcleral tissue. Whether treated or not, the condition is self-limited after a few days, and although it may recur over a period of many years it rarely leaves any residual ocular damage. In two-thirds of the cases, the disease is considered idiopathic.

4.1.2Patient Characteristics

Episcleritis occurs in young adults, usually women, with a peak incidence in the fourth decade [3]. In our series of patients with episcleritis (Table 4.2), the mean age of onset of the Þrst episode was 47 years. Episcleritis was three times as common in women as in men. Although episcleritis may affect individuals of all races, there are no studies on the incidence and prevalence within racial groups. Some early reports

suggested that the condition had a Mendelian dominant transmission; [15, 16] our experience shows that episcleritis is not per se a hereditary condition, although some of the episcleritis-asso- ciated systemic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, reactive arthritis, BehcetÕs disease, gout, and atopy, have a genetic basis.

4.1.3Clinical Manifestations

Episcleritis is usually characterized by recurrences involving different eyes at different times and affecting one area after another. Sometimes, however, the patient develops the inßammation in both eyes at the same time. Over 60% of patients with episcleritis may have recurrences for 3Ð6 years after the onset of the disease, but the episodes become less frequent after the Þrst 3Ð4 years, until the problem no longer recurs [2, 3]. In a series of patients with episcleritis, the duration ranged from 1 month to 38 years [15]. Bilaterality was found in 40% of our patients (Table 4.2). The main symptom is mild discomfort, which can be described as a feeling of heat, sharpness, or irritation, and the main sign is redness, which can be localized in one sector or can involve the whole episclera. Pain, if any, is usually

described as a slight ache localized to the eye. On rare occasions, severe pain radiating to the forehead and tenderness to the touch may be present, but these symptoms are more commonly characteristic of scleritis; if marked pain and/or tenderness to touch exists in a patient who appears clinically to have episcleritis, the likelihood is considerable that in fact the patient has some component of occult scleritis. Redness, best examined in daylight, may range in intensity from a mild red ßush to Þery red, but it is not accompanied by the bluish tinge present in scleritis. In a severe attack of episcleritis, lid swelling and associated spasm of the sphincter of the iris and ciliary muscle, resulting in miosis and temporary myopia, may occur, but this is a rare occurrence. Other symptoms include tearing (never true discharge) and mild photophobia.

Clinical examination with the slit lamp, particularly with red-free light, discloses that the inßammation is entirely localized within the episcleral tissue. The underlying sclera is never involved. The superÞcial edge of the narrow beam of the slit lamp is displaced forward, showing the episcleral edema. The deep edge of the narrow beam of the slit lamp remains ßat against the sclera, showing no displacement forward by underlying scleral edema. The distribution of inßammation is more common in the interpalpebral

Fig. 4.1 Episcleritis prior to instillation of 10% phenylephrine drops

Fig. 4.2 Same eye as in Fig. 4.1 after the instillation of 10% phenylephrine drops. Note the dramatic reduction in the inßamed appearance of the globe, because of the vasoconstrictor effect on the episcleral vascular plexuses, indicating that this patient probably has episcleritis rather than true scleritis

area (Fig. 3.1 in Chap. 3) [17, 18]. The superÞcial episcleral vessels, following the usual radial pattern, appear congested with little coexisting congestion of the overlying conjunctival vessels and the underlying deep episcleral vessels, and without coexisting congestion of the scleral vessels. Topical phenylephrine (10%) or epinephrine (1:1,000) instilled in the cul-de-sac has a greater vasoconstrictor effect on the episcleral vessels than on the scleral vessels. This is a useful method for distinguishing episcleritis (where redness should diminish greatly) (Figs. 4.1 and 4.2) from scleritis (where redness should be minimally

affected by these drugs) [3]. The edema of the episcleral tissue is diffusely distributed and sometimes manifests itself as subconjunctival grayish inÞltrates that appear yellow when viewed with a red-free light. These inÞltrates have been shown to be composed of inßammatory cells, particularly lymphocytes.

Although episcleritis usually does not develop into scleritis, scleritis produces an overlying episcleritis. None of our patients with episcleritis developed scleritis, even after many recurrences and a long duration of the disease. Episcleritis rarely causes loss of vision because the associated complications, such as corneal involvement or uveitis, are uncommon and are never severe. In our series of patients with episcleritis, only 2.3% had decrease in vision (deÞned as loss of two or more lines on the Snellen eye chart at the end of the follow-up period or visual acuity of 20/80 or less at presentation (Table 4.2)). This decrease in vision was attributed to cataracts in all of the patients. Mild peripheral corneal changes, such as superÞcial and midstromal inßammatory cell inÞltration, can be observed occasionally in patients with episcleritis in the area adjacent to the conjunctival and episcleral edema, but these inÞltrates never progress to corneal ulceration. They rarely are permanent unless the attacks are recurrent in the same area. None of our patients with episcleritis had peripheral ulcerative keratitis (PUK). Intraocular structures are almost never involved. In a small minority of cases, cells in the anterior chamber and aqueous ßare may appear, but these are never severe. Sixteen percent of our patients with episcleritis developed a mild anterior uveitis (Table 4.2). Intraocular hypertension and cataract are not directly attributed to the episcleral inßammation unless they are induced by steroid treatment [2, 18]. Although transient diplopia has been reported in patients with episcleritis, there is no clear association between extraocular muscle imbalance and episcleral inßammation [18].

Anterior segment ßuorescein angiogram shows a rapid Þlling of all the vascular networks, but the vascular pattern itself remains normal.

Leakage from all vessels is rapid but remains to that usually seen in normal conjunctiva or episclera.

4.1.4Classification of Episcleritis

Episcleritis may be divided into subcategories of simple episcleritis and nodular episcleritis. Both have the same characteristics described above, but they differ in the onset of the signs and symptoms, localization of the inßammation, and clinical course.

4.1.4.1 Simple Episcleritis

Simple episcleritis is more common than nodular episcleritis (Table 4.1). The involved area appears diffusely congested and edematous (Figs. 3.1, 3.2, 3.18, 3.19, 3.22, and 4.1). The onset of redness is usually rapid after the symptoms appear, reaching its peak in a few hours and gradually subsiding over a period varying from 5 to 60 days. In a study performed by Watson and coworkers [19], in which they assessed the efÞcacy of two different topical anti-inßammatory drugs, the majority of the attacks in patients of the control group (placebo) lasted between 5 and 10 days. Each attack is self-limited and usually clears without the need for treatment. Recurrence in the same or opposite eye, involving the same or different areas, may occur within a period of 2 months. Over 60% of patients with simple episcleritis have recurrences for 3Ð6 years after the onset of the disease, but the episodes become less frequent after the Þrst 3Ð4 years until the disease no longer recurs [2, 3].

There is a less deÞned group of patients who, instead of having numerous evanescent attacks, have a few prolonged ones. These patients are predominantly the ones who have some associated disease. Most of our patients with infectious etiologies had one long episode which resolved completely after appropriate treatment.

4.1.4.2 Nodular Episcleritis

In nodular episcleritis, the onset of redness gradually increases over a period of 2Ð3 days. As

Fig. 4.3 Nodular episcleritis. The nodule is mobile, that is, not incorporated into sclera or part of sclera

simple episcleritis, the inßammation of nodular episcleritis is localized to the episclera; unlike simple episcleritis, however, the inßammation of nodular episcleritis is conÞned to a very welldeÞned area, forming a slightly tender, dark red nodule with little surrounding congestion (Fig. 4.3). The nodule, usually round or oval, enlarges rapidly and varies from 2 to 6 mm or larger in size [20, 21]. The overlying conjunctiva can be moved over the surface of the nodule which in turn moves slightly on the underlying sclera. The episcleral nodule evolves over a chronic course of inßammation, becoming paler and ßatter, usually after 4Ð6 weeks, and then disappears entirely. When the episcleral nodule disappears, the underlying sclera appears normal. If there is increased residual scleral translucency, scleral inßammation instead of episcleral inßammation should be suspected; however, repeated attacks of nodular episcleritis localized at the same site for many years may increase scleral translucency. Recurrences in the same site on the same eye, at a different site on the same eye, or on the other eye may occur, sometimes with more than one nodule at a time. The episcleral nodule can be differentiated from a conjunctival phlyctenule because the overlying conjunctiva can be moved over the episcleral nodule [21]. The episcleral nodule can be differentiated from a scleral nodule by slit-lamp examination, particularly with a red-free light; the deep edge of the narrow beam of the slit lamp remains ßat