nodules that gradually develop a necrotic slough or sequestrum without surrounding inßammation; this sequestrum eventually separates from the underlying sclera, leaving the choroid bare or covered only by a thin layer of conjunctiva (Fig. 4.21) [56]. The choroid does not bulge through these areas unless the intraocular pressure rises. Although spontaneous perforation is rare, traumatic perforation may easily occur [1, 3, 57]. If the perforation is not repaired, phthisis bulbi will occur [57]. Because the condition presents with an insidious onset, slow progress, and lack of pain or tenderness to the touch, it is detected by the patientÕs family, by the patient while looking in the mirror, or by the rheumatologist by chance; they notice the yellow or grayish patch or patches on the sclera, anywhere between the corneal limbus and the equator.

One of the Þrst characteristic Þndings which can be seen on slit-lamp examination is a reduction in the number and size of vessels in the episclera surrounding the sequestrum, giving a porcelain-like appearance. These vessels anastomose with each other and sometimes cross the abnormal area to join with perilimbal vessels. As the necrotic process progresses, the sequestrum is gradually removed. Fluorescein angiography shows that the necrotic process in scleromalacia perforans appears to be caused by arteriolar obliteration, unlike in necrotizing scleritis, in which the necrotic process appears to be caused by venular obliteration [4, 5].

van der Hoeve originally noticed [56, 58] and other authors subsequently conÞrmed [2, 59Ð67] the association of these ocular changes with severe, progressive, long-standing rheumatoid arthritis with extraarticular manifestations. In our series, 67% of patients with scleromalacia perforans had an associated disease (Table 4.4) that was, in all cases, long-standing rheumatoid arthritis (Table 4.5). The characteristic sufferer of this condition is a woman with an age range from 49 to 74, most commonly in the sixth decade (Table 4.4).

Keratitis, uveitis, glaucoma, cataract, and macular edema may appear and lead to decrease in vision. In our series, 33% of the patients with scleromalacia perforans had decrease in vision (Table 4.4).

Fig. 4.21 Scleromalacia perforans in a patient with rheumatoid arthritis. Note the extraordinary degree of scleral loss, with uveal bulge under the stretched conjunctiva

Differential Diagnosis

Differential diagnosis of scleromalacia perforans includes necrotizing scleritis with inßammation and scleral degenerations, such as paralimbic (or intercalary) scleromalacia and senile hyaline plaques (Table 4.6).

Necrotizing Scleritis with Inflammation

The presence of pain and active inßammation helps to differentiate this entity from scleromalacia perforans. Furthermore, in necrotizing scleritis with inßammation, the involvement is most frequently unilateral and the association with rheumatoid arthritis is variable.

Paralimbic Scleromalacia

Paralimbic scleromalacia appears to be a degenerative process that occurs at the corneoscleral limbus of either one or both eyes, and is characterized by a slowly progressive, noninßammatory, painless scleral thinning that leads to a spontaneous small perforation with iris prolapse [5, 21, 63, 67Ð71]. In slit-lamp examination, a small hole in the limbal sclera can be seen with incarceration of iris covered by conjunctiva; the appearance resembles the Þltering bleb of an Elliot trephining operation. Sometimes, the pupil may be peaking toward the area of iris incarceration, but because the hole is small there is no need for surgical closure. A small perforating scleral vessel may run through the defect to anastomose with the posterior ciliary circulation [5]. The intraocular pressure