Clinical Characteristics of Subretinal Precipitates in Epidemic Retinitis

Purpose: To characterize subretinal precipitates in epidemic retinitis and assess their clinical significance as a resolving-stage manifestation. Methods: This retrospective observational study included 113 patients with epidemic retinitis, categorized into 2 groups based on the presence or absence of subretinal precipitates. Clinical, imaging, and treatment data were analyzed. A subgroup presenting within 20 days of symptom onset (n = 76) was categorized and underwent additional assessment. Results: Of 113 patients, 33 (29.2%) had subretinal precipitates (group A), and 80 did not (group B). Subretinal precipitates appeared as yellow granular lesions, mostly in the inferior fundus (78.8%). Optical coherence tomography scans of the subretinal precipitates demonstrated associated subretinal fluid (SRF) in 11 (37.9%) of the 29 available cases. In the 18 remaining cases, a predominantly inferior gravitational distribution, and in some eyes crescentic configuration, raised the possibility of previously resolved SRF. Fundus autofluorescence failed to detect subretinal precipitates. In subgroup analyses, those with subretinal precipitates (n = 22) had a larger retinitis area (mean 17.28 mm 2 versus 11.9 mm 2 ; P = .16) and higher proportion of oral corticosteroid use (40.9% versus 24.1%; P = .23) than those without subretinal precipitates (n = 54), but differences were not significant. Similarly, no significant differences between subgroups with and without subretinal precipitates were observed in SRF height, number of retinitis patches, final visual acuity, or time to resolution of retinitis and macular edema (each P > .05). Subretinal precipitates developed after a mean 1.1 months (range, 0.5–2 months) and resolved after a mean 5.3 months (range, 2–10 months). Conclusion: Subretinal precipitates are a notable resolving-stage manifestation of epidemic retinitis that may persist for months. Recognition of their characteristic features, particularly in patients with a recent febrile illness, may facilitate the diagnosis of resolving epidemic retinitis.