may be low when the perforation occurs but rises rapidly to normal as soon as the iris incarcerates. Paralimbic scleromalacia is a rare condition affecting individuals of either sex between the ages of 25 and 50 years, without evidence of systemic disease or previous ocular inßammation. If there is association with rheumatoid arthritis, the condition should probably be regarded as necrotizing scleritis without inßammation or as scleromalacia perforans. Paralimbic scleromalacia has a good prognosis without treatment.

Senile Scleral Hyaline Plaques

Senile scleral hyaline plaques also can be mistaken for scleromalacia perforans because both lesions involve loss of scleral substance, lack of inßammatory reaction, and painless development [58, 69, 70]. The scleral plaque, which occurs in individuals of either sex between the ages of 60 and 75 years, appears as a dark, oval, nonprogressive patch with a size ranging from 1 to 2 mm in width and 2Ð6 mm in length [5, 21, 63, 72Ð79]. The lesion, usually bilateral and symmetrical, is localized to the interpalpebral region, between the insertion of the lateral or medial rectus muscles and the limbus (Chap. 3, Fig. 3.16). In slitlamp examination, the plaque appears as a translucent area through which the underlying uvea can be seen, surrounded by a calcareous yellowish ring and covered by atrophic episclera and normal conjunctiva. The central translucent area can be transilluminated by directing the light

through the pupil, but although the sclera is thinned (from 0.6 to 0.3 mm) [78] the wall is resistant, with no tendency to perforation. Histologically, it is considered as a degenerative lesion with a lack of cellular elements, replacement of the superÞcial layers of the sclera by large masses of hyaline degeneration, and calciÞcation. The collagen Þbers in the area adjacent to the plaque are fragmented and swollen, making the sclera weak. The location of the plaque, therefore, may be determined by the maximal stresses of the muscles. Senile scleral plaque has a good prognosis without treatment because there is no evidence of systemic disease or previous ocular inßammation associated with this condition.

4.2.4.5 Posterior Scleritis

Posterior scleritis accounts for the inßammation of the sclera posterior to the ora serrata, which may spread to the posterior segment of the eye, involving choroid, retina, and optic nerve. Thus, because a fundus mass, choroidal folds, retinal striae, choroidal or retinal detachments, and disk or macular edema may appear, posterior scleritis may be confused with many other diseases, such as primary or secondary choroidal tumors, uveal effusion syndrome, rhegmatogenous retinal detachments, VogtÐKoyanagiÐHarada syndrome, central serous retinal detachments, and optic neuritis [4, 80Ð86]. Because posterior scleritis also may extend outward, involving extraocular muscles and orbital tissues, it also may be

confused with orbital tumors or orbital inßammatory diseases [84, 87, 88]. Furthermore, posterior scleritis is often associated with anterior scleritis; but it also may occur alone, in which case the absence of anterior scleral involvement makes the diagnosis difÞcult [1, 2, 7, 8, 84]. And if the concomitant anterior scleritis is severe, posterior scleritis may be overlooked. Therefore, posterior scleritis is a more common condition than is realized, and the diagnosis is often missed or delayed [1, 3Ð5, 7]. Recognition of the protean clinical manifestations and conÞrmation by ancillary testing are important to reach a correct diagnosis of posterior scleritis. Early diagnosis leads to early therapy and prevention of complications that could cause permanent decrease in vision.

Posterior scleritis may be a posterior extension of either nodular or diffuse anterior scleritis. In our series, anterior scleritis was present or had occurred in 21 of 31 patients (68%) with posterior scleritis. Posterior scleritis may present alone, in which case anterior involvement may or may not appear later [3]. Evidence of posterior scleritis must, therefore, be searched for during the course of an anterior scleritis, although the absence of anterior scleritis does not exclude the possibility of posterior scleritis.

Symptoms and Signs

Symptoms and signs at presentation are variable because they depend on the degree and site of inßammation. The most common presenting symptoms are decrease in vision and pain, although diplopia, ßashes, and tenderness may also be present [3, 7, 86]. The most common presenting sign is redness, related to anterior scleritis; conjunctival chemosis, proptosis, lid swelling, lid retraction, and limitation of ocular movements may also be detected [3, 7, 86].

Some decrease in vision is almost always present and its severity depends on the site, type, and degree of the complications associated. The reduction in vision may reßect a transient hyperopia, which is caused by a decrease in the axial length of the globe secondary to posterior scleral thickening [85, 89, 90]. In these cases, patients complain of mild

decrease in vision and asthenopia, which can be corrected with the addition of convex lenses. In other cases, the reduction in vision is not correctable because it is caused by severe complications, such as choroidal or retinal detachments, distortion of the macula by an area of scleral inßammation, cystoid macular edema, and optic neuritis [7, 8, 84Ð86, 91, 92]. These complications are frequently reversible, with a good visual outcome if adequate treatment for posterior scleritis is initiated shortly after its onset. If diagnosis and treatment are delayed, permanent damage may cause irreversible decrease in vision [7]. In our series, decrease in vision as the initial symptom was noted by 280 of the 31 patients (90%) with posterior scleritis.

The pain varies from mild to severe and often is referred to the brow, temple, face, or jaw. In our series, pain was present in all of the 311 patients (100%) with posterior scleritis; of these, 3 patients described pain as severe, 18 as moderate, and 10 as mild. The pain is often correlated with the severity of the anterior involvement, and therefore patients with posterior scleritis alone have either no pain or pain of a mild degree [7, 84]. Mild pain may result from stretching of TenonÕs capsule by edema, stretching of scleral sensory nerve endings by edema, optic nerve sheath swelling, or orbital or extraocular muscle swelling [85]. All 21 patients with posterior scleritis who described the pain as severe or moderate also had anterior involvement. Photopsia may occur secondary to retinal striae or retinal detachment.

The sclera and TenonÕs capsule are closely connected, especially around the optic nerve and behind the limbus. Similarly, the connective tissue of the orbit and the connective tissue of the muscle sheaths form a direct continuation of TenonÕs capsule. Extension of posterior scleral inßammation to the orbit explains the signs of proptosis, chemosis, lid swelling, and lower lid retraction with upgaze. Extension of posterior scleral inßammation to the extraocular muscles causes myositis which may lead to diplopia and ptosis due to ocular movement impairment [92].