Localization of multifocal electroretinogram abnormalities to the lesion site: findings in a family with Best disease.

OBJECTIVE To determine the association between multifocal electroretinogram (mfERG) abnormalities and macular lesions, as shown by retinal photography and optical coherence tomography (OCT), in a 3-generation family with vitelliform macular dystrophy. METHODS Five family members were examined using OCT, mfERG, and retinal photography. To localize mfERG abnormalities in relation to retinal findings, we overlaid the mfERG trace arrays on the retinal images and aligned the mfERGs and OCT images in the 180 degrees meridian. RESULTS Family members had typical macular lesions, normal full-field ERGs, and reduced electro-oculogram light-dark ratios. The OCT images demonstrated variable lesion severity. Some individuals with good vision and normal-appearing fundi showed OCT abnormalities of the choroid and retinal pigment epithelium. The overlay technique revealed that the depressed mfERGs corresponded with the lesions detected by OCT and retinal photography. The latencies of mfERG components in the 2 central stimulus rings in our patients were often prolonged. CONCLUSIONS The mfERG abnormalities matched the localization of the macular lesions in our patients. The latencies of the mfERG N1 and P1 components in the first 2 concentric stimulus rings were often significantly (>2 SDs) delayed, an observation that has not been previously reported, to our knowledge.