Fundus Autofluorescence Findings in Eyes With Birdshot Chorioretinitis

The purpose of this study was to describe fundus autofluorescence (FAF) findings in eyes with birdshot chorioretinitis (BSCR) and to compare findings to demographic, medical, and clinical characteristics.

In this multicenter, prospective, cross-sectional study, 172 eyes (86 patients) with BSCR were investigated. Participants underwent a standardized evaluation including collection of demographic data, ophthalmic and treatment history, and ophthalmologic examination. Using a standardized protocol, hypo- and hyperautofluorescence in macular and extramacular regions and specific patterns of abnormal FAF could be scored for 167 eyes. Images were scored by two independent, masked graders. Measures of visual function included best-corrected visual acuity (BCVA), contrast sensitivity (CS), color vision, and Humphrey visual field mean deviation (HVF-MD).

Any abnormal FAF finding was observed in 132 eyes (79.0%); macular abnormalities were observed in 84 eyes (49.1%). The most common findings were peripapillary confluent hypoautofluorescence (122 eyes [73.1%]); extramacular granular hypoautofluorescence (100 eyes [59.9%]); and macular granular hypoautofluorescence (67 eyes [40.1%]). Confluent hypoautofluorescence was related to longer median disease duration (8.7 years) than granular hypoautofluorescence (7.9 years) or hyperautofluorescence (5.6 years). Macular confluent hypoautofluorescence was associated with BCVA ≤20/25 (odds ratio [OR] = 7.83, P = 0.007), BCVA ≤20/50 (OR = 4.94, P = 0.002), and abnormal CS (OR = 4.56, P = 0.009). Presence of macular or extramacular hypoautofluorescence was related to HVF-MD ≤-3 dB (OR = 2.43, P = 0.01 and OR = 2.89, P = 0.003, respectively).

In this large cohort, various FAF abnormalities were found, indicating that disorders of the retinal pigment epithelium are features of BSCR. Abnormal FAF is a marker of visual dysfunction in the disease.