Comparison of Pattern ERG, Multifocal ERG and Psychophysical Correlates of Fundus Autofluorescence Abnormalities in Patients With Cone–rod (RPGR, RIM1) or Rod–cone Dystrophy

Abstract

Abstract: : Purpose: To compare multi–focal and pattern electroretinography (mfERG, PERG) and fine matrix mapping (FMM) in patients with cone–rod or rod–cone dystrophy and annular macular abnormalities present on fundus autofluorescence imaging (AF). Methods: Fundus AF was performed on patients with cone–rod (CORDX1 associated with RPGR or CORD7 associated with RIM1) or rod–cone dystrophy diagnosed by ISCEV–standard ERGs. Mf ERG, PERG and fine matrix mapping (FMM) were performed. Results: Patients with cone–rod dystrophy had annuli of high density AF that bordered central areas of low density in older RPGR cases and most RIM1 cases. PERG P50 amplitude was inversely related to the size of the AF ring. In two RPGR patients, mfERGs showed widespread reduction with relative sparing over the foveal area. FMM showed reduced sensitivity, worse over areas of high density AF. In RIM1 patients, high density areas bordered central atrophic lesions and were spatially concordant with a gradient of sensitivity loss. AF rings encircled areas of preserved photopic function in rod–cone dystrophy with normal acuity. One patient, monitored over 4 years, showed AF evidence of progressive constriction of the ring of increased AF. Conclusions: The high correspondence between PERG, mfERG and fine matrix mapping in patients with cone–rod and rod–cone dystrophy and abnormalities in autofluorescence imaging, suggests that high density areas of autofluorescence reflect underlying functional disturbances. AF rings may constrict with time in patients with rod–cone dystrophy.

Keywords: retinal degenerations: hereditary • electroretinography: clinical • imaging/image analysis: clinical