When considering the differential diagnosis of SO, it is important to rule out intraocular infections that could cause severe endophthalmitis. Posttraumatic iridocyclitis may also cause an inflammatory reaction, but neither endophthalmitis nor iridocyclitis involves the fellow eye.

The differential diagnosis also includes any other cause of granulomatous uveitis, especially phacoanaphylaxis, Vogt–Koyanagi–Harada disease (VKH), sarcoidosis, or posterior scleritis (Box 81.2).

Phacoanaphylaxis is a chronic granulomatous inflammation that occurs following traumatic or surgical lens capsule disruption and could closely simulate the clinical signs of SO. It typically manifests as a granulomatous anterior uveitis. The choroid, retina, and optic nerve are not usually involved in the disease process. Studies have shown that phacoanaphylaxis can coexist with SO (4–25%), and even though phacoanaphylaxis is normally a unilateral inflammation, bilateral occurrence has been …