2020–2021 BCSC Basic and Clinical Science Course™
4 Ophthalmic Pathology and Intraocular Tumors
Part I: Ophthalmic Pathology
Chapter 8: Sclerax
Inflammation
Scleritis
Scleritis may be infectious or noninfectious. Infectious scleritis may be distinguished from noninfectious scleritis by appropriate laboratory testing; special stains may aid in identifying causative organisms (Fig 8-3).
Noninfectious scleritis is typically a painful ocular disease with potentially serious sequelae. Histologic examination of noninfectious scleritis reveals 2 main types: necrotizing and nonnecrotizing inflammation. Either type can occur anteriorly or posteriorly, but anterior scleritis is more common. Necrotizing scleritis may be nodular or diffuse (Figs 8-4, 8-5). Both forms demonstrate granulomatous inflammation within the sclera (Fig 8-6). Lymphocytes and plasma cells are usually present as well. Neutrophils may be present in some cases. Multiple foci may show different stages of evolution. In the course of healing, the necrotic stroma is resorbed, leaving a thinned scleral remnant that is prone to staphyloma formation (Fig 8-7). Severe ectasia of the scleral shell predisposes the sclera to herniation of uveal tissue through the defect (staphyloma). In scleromalacia perforans, the sclera undergoes focal progressive ectasia without clinical or histologic evidence of an inflammatory infiltrate. The ectasia can lead to scleral perforation requiring urgent medical and surgical intervention.
Nonnecrotizing scleritis is characterized by a perivascular lymphocytic and plasmacytic infiltrate, typically without a granulomatous inflammatory component. Vasculitis may be present in the form of fibrinoid necrosis of the vessel walls. When treated, nonnecrotizing scleritis rarely leads to severe vision loss or enucleation.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.