Outer Retinal Alterations Associated With Visual Outcomes in Best Vitelliform Macular Dystrophy

Abstract

To describe outer retinal structure in patients with Best vitelliform macular dystrophy (BVMD) using spectral-domain optical coherence tomography (OCT) and correlate these results with best-corrected visual acuity (BCVA) and patient age. Retrospective cross-sectional study. Patients with molecularly confirmed BVMD were compared with normal control subjects (NCs). A complete clinical evaluation was performed, including BCVA, fundus photography, spectral-domain OCT, and fundus autofluorescence. Spectral-domain OCT images were analyzed to determine the stage of the lesion, the central macular thickness (CMT), the foveal outer nuclear layer (ONL) thickness, and tomographic structural changes. Forty-two patients with BVMD (42 eyes) with a molecular diagnosis and 42 NCs (42 eyes) were included. Clinical stages (Gass clinical classification) were distributed as follows: 4.8% for stage 1, 23.8% for stage 2, 16.6% for stage 3, 45.2% for stage 4, and 9.5% for stage 5. The presence of subretinal fluid and vitelliform material was noted in 76% and 79% of the BVMD eyes examined, respectively, and was not associated with BCVA modification (P= .758 and P=.968, respectively). The median ONL thickness was significantly lower compared with the NCs (P<.001). BCVA was significantly correlated with stage (R= 0.710; P < .01), age (R= 0.448; P < .01), CMT (R=-0.411; P < .01), and ONL thickness (R=-0.620; P < .01). The disruption of the external limiting membrane and the ellipsoid zone was associated with a decreased BCVA (P < .001 for both). Among the 32 eyes with subretinal detachment, photoreceptor outer segment length was significantly correlated with BCVA (R=-0.467; P < .01) and ONL thickness (R= 0.444; P= < .01). This study shows the correlation between BCVA, age, and spectral-domain OCT features in patients with BVMD. ONL thickness as well as photoreceptor outer segment length are relevant functional correlates and outcome measures to follow photoreceptor impairments and disease progression.