Purpose
Birdshot chorioretinopathy (BSCR) is a rare form of posterior uveitis typically characterized by clinical findings and imaging features. Clinical and imaging data was evaluated retrospectively to characterize the correlation between visual field defects and fundus autofluorescence in patients with BSCR.
Methods
Manual Goldmann visual fields (GVF) and ultra-wide field fundus autofluorescence (FAF) (Optos P200Tx, Optos, Scotland, UK) were obtained from 8 eyes of 5 patients with BSCR. Inclusion criteria included ability to fixate reliably. Adobe Photoshop Elements 11.0 (San Jose, CA) was used to standardize the images. Overlap analysis was performed using ImageJ software (NIH, Bethesda, MD) by measuring areas of overlap of hypo-autofluorescent (suggestive of advanced disease) FAF lesions and GVF scotomas as defined by the V4e isopter in the central 60°. The optic nerve and physiologic blind spot were excluded in the area analysis. Overlap was calculated as a percentage of the total area identified on FAF and GVF, respectively. Average areas for FAF and GVF were calculated.
Results
Ages of patients ranged from 52 to 82 years old with a mean of 65 ± 11. 14 ± 23% of the total area identified as hypo-autofluorescent FAF lesions overlapped with scotoma. On the other hand, 28 ± 41% of the area covered by GVF scotomas overlapped with hypo-autofluorescent FAF lesions. Average area of FAF hypoautofluorescence was much larger (18.77 disc areas) than on GVF (2.56 disc areas).
Conclusions
There appears to be larger total areas of hypo-autofluorescence on FAF than scotoma evident by GVF. In this study, less than half of the abnormal area identified by FAF and GVF overlapped. There was a greater percentage of overlap of GVF compared to FAF. The results of this study underscore the need to follow patients with BSCR using multi-modal imaging as each technique may contribute different information about the disease status.