Electroretinographic findings in Fuchs' heterochromic cyclitis

Purpose: Fuchs' heterochromic cyclitis (FHC) is an inflammatory disease of unknown aetiology. Although anterior segment signs and vitreous changes are well recognised, retinal features are unusual. To assess the extent of retinal involvement, we performed electrophysiological testing in a group of FHC patients. Methods: Retinal function was assessed by means of flash electroretinogram (ERG) using a Ganzfeld stimulus, and pattern electroretinogram (PERG) using a checkerboard stimulus of spatial frequency 0.5 and 1.0 cycle per degree reversing at 6 Hz. A total of 21 patients with unilateral, normotensive FHC with visual acuities of 6/5 to 6/9 were studied. Results: In the flash ERG, selective scotopic b-wave abnormalities occurred in 9 (43%) of 21 FHC eyes. Despite clear media and no history of ocular surgery, 7 patients showed abnormalities of the PERG. Conclusions: These electrophysiological findings suggest subclinical damage to the inner retinal layers, but not involving the photoreceptors, in eyes with FHC.