Early Detection of Central Visual Function Decline in Cone-RodDystrophy by the use of Macular Focal Cone Electroretinogram

PURPOSE: To evaluate macular focal cone ERG (fERG) as a tool for reliable and early detection of central retinal function decay in cone-rod dystrophy (CRD). RESULTS: Macular focal cone ERG follow-up allowed a clear-cut identification of CRD patients as stationary or progressive, in agreement with visual acuity follow-up. In all progressive patients, fERG declined whenever visual acuity declined, and--in 50% of the cases--fERG loss anticipated acuity loss of several years. CONCLUSIONS: Macular focal cone ERG represents a sensitive assay to detect, categorize, and follow the progression of central retinal dysfunction in CRD. Its use as a diagnostic tool in CRD may help anticipate, for an individual patient, the likelihood and rate of further disease progression before visual acuity loss has occurred.