Diagnostic Challenge of Adult-onset Vitelliform Macular Dystrophy

The aim of this study is to present the structural and functional changes in patients with adult-onset vitelliform retinal dystrophy (AOVMD) initially misdiagnosed as age-related macular degeneration or central chorioretinitis. Twelve eyes of six patients with AOVMD underwent a complete clinical examination, fundus autofluorescence (FAF), fluorescein angiography (FA), optical coherence tomography (OCT), electrophysiological studies – full-field and multifocal electroretinography (ffERG and mfERG), thanks to which the diagnosis was established, and confirmed genetically. A classic phenotype of AOVMD was found in twelve eyes of six women in adulthood (from 41 to 69 years old) with slightly reduced visual acuity, and altered colour vision in two patients. On FAF, hyperautofluorescence was found in the macular area in each eye. On OCT, bilateral yellowish rounded subfoveal deposits in the retinal pigment epithelium (RPE) were visualized, on FA – hypo- and hyperfluorescent zones in the foveal area were found in all eyes with partial resorption and atrophic areas in the RPE in two eyes. The electrophysiological studies found absence of diffuse photoreceptor involvement. The local mfERG photopic response was mildly decreased, to a greater extent in the oldest female. The relatively good functional results in contrast to the pronounced structural changes support the diagnosis, confirmed also genetically. Adult-onset hereditary retinal dystrophy is a diagnostic challenge that requires thorough clinical, electrophysiological, and genetic testing to distinguish it from some acquired retinal diseases.