A wide variety of agents can infect the sclera, including Pseudomonas organisms (most common after pterygium excision), Actinomyces and Nocardia species, mycobacteria, fungi such as Fusarium and Aspergillus species, and gram-positive cocci (Staphylococcus pneumococcus and Streptococcus species). In addition, herpes simplex virus and varicella-zoster virus can cause chronic infectious scleritis. Infectious scleritis can occur after any previous ocular surgery, including pterygium surgery (especially when beta radiation or mitomycin C is used), scleral buckling, cataract surgery, and pars plana vitrectomy. Trauma with a penetrating injury contaminated by soil or vegetable matter may also result in infectious scleritis.
Infectious scleritis can present with pain, redness, and decreased vision, as with noninfectious scleritis. Nodular and necrotizing scleral disease are more common in this setting, and patients may also have intraocular inflammation (sclerouveitis) that is disproportionately more significant than that seen in noninfectious scleritis. A precipitating surgery may be recent or remote (in rare cases, many years before). The sclera appears necrotic, thin, and avascular, with inflammation at the edges (see Fig 7-3), usually at the site of a surgical or traumatic wound. A mucopurulent discharge may be present, depending on the infectious agent.
Raiji VR, Palestine AG, Parver DL. Scleritis and systemic disease association in a community-based referral practice. Am J Ophthalmol. 2009;148(6):946–950.
Riono WP, Hidayat AA, Rao NA. Scleritis: a clinicopathologic study of 55 cases. Ophthalmology. 1999;106(7):1328–1333.
Watson PG, Hazleman BL, McCluskey P, Pavésio CE. The Sclera and Systemic Disorders. 3rd ed. London: JP Medical; 2012.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.