The Characterization of Retinal Bestrophinopaties, and Pseudovitelliform Dystrophies using Polarisation Sensitive Optical Coherence Tomography

Abstract

Purpose: The aim of the study was to investigate whether bestrophinopathies with different genetic background show different characteristics on polarization sensitive OCT, that would further facilitate the differential diagnosis of these diseases.

Methods: In this prospective case series 25 eyes of 13 patients were enrolled with fundus changes compatible with Best dystrophy or pseudovitelliform dystrophy. All patients underwent a complete ophthalmologic examination including OCT, fundus autofluorescence (FAF), electrooculography (EOG), polarization sensitive OCT (PS-OCT), and PCR plus direct sequencing for the BEST1 gene.

Results: After EOG examination and genetic testing for the BEST1 gene the diagnosis of Best dystrophy (BD) was made in 5 patients, autosomal recessive bestrophinopathy (ARB) in 2 patients, and pseudovitelliform dystrophy (PVMD) in 6 patients. The PS-OCT showed a characteristic pattern in case of BD and PVMD with non-depolarizing material in the subretinal space consistent with the yellowish lipofuscin accumulation seen on funduscopy with an intact or somewhat freckled retinal pigment epithelium (RPE) line below it. In these cases subretinal deposits depolarizing equally to the RPE or RPE thickenings were seen under the non-depolarizing material. In case of ARB although funduscopically the lipofuscin accumulations seemed similar to those as seen in patients with BD, on PS-OCT they seemed to be in the sub RPE space instead of the sub-retinal space as seen in the other entities. The RPE was mostly freckled and sometimes thickened above the non-depolarizing lipofuscin material.

Conclusions: Bestrophinopathies and pseudovitelliform dystrophies showed characteristic patterns on PS-OCT. Interestingly the autosomal recessive mutation of the BEST1 gene caused the lipofuscin to accumulate in a different compartment than the disease caused by the dominant mutation of the same gene or even in pseudovitelliform dystrophy.

Keywords: 696 retinal degenerations: hereditary • 550 imaging/image analysis: clinical