Best Vitelliform Macular Dystrophy

Autosomal recessive bestrophinopathy (ARB) results from a total absence of functional bestrophin-1 protein owing to two BEST1 mutations, one on each of the chromosomes. If present at an early age, the presenting feature could be decreased vision due to amblyopia. Refractive error is hyperopia, predisposing these eyes for acute angle-closure glaucoma. The yellowish lesions are larger and more extensive-extending beyond the arcades-than in the typical autosomal dominant Best disease. Some of the eyes also show numerous yellowish subretinal dots. Lesions are multifocal (Fig. 29.1). Subretinal fibrosis in the macular area is a common feature. Optical coherence tomography (OCT) may show cystoid changes in the neurosensory retina. Fundus autofluorescence (FAF): Increased AF reflects lipofuscin accumulation in the RPE; decreased AF reflects RPE atrophy. Electroretinography (ERG): As panretinal photoreceptor dysfunction progresses with advancing age, full-field (FF) ERG shows delayed rod and cone responses. Electrooculography (EOG): Abnormal Arden ratio.