Decreased Retinal Sensitivity Overlying Choroidal Nevi.

Purpose: To report retinal function findings on the choroidal nevus.

Methods: Prospective descriptive case series of 7 patients (n = 7 eyes) presenting a melanocytic choroidal lesion consistent with choroidal nevus and no other ocular disease. Baseline evaluation included measurement of best-corrected visual acuity (BCVA), color and near-infrared fundus pictures, and spectral-domain OCT (Heidelberg Engineering). Retinal function was tested with microperimetry (MAIA; CenterVUE, Padova) using a standard grid (µP1) and a linear grid (µP2) that distribute test points on retinal areas that overlaid the choroidal lesion as well as lesion-free areas equidistantly to the fovea in 3 parallel lines. mfERG was performed following the International Society for Clinical Electrophysiology of Vision (ISCEV) recommendation using a 61-hexyagon protocol.

Results: BCVA was 20/25 (0.1 logMAR) or better in all 7 eyes. Microperimetry showed central stable fixation on all eyes, with mean ± SE sensitivity threshold significantly decreased on retinal areas overlaying the lesions (µP1): 21.8 ± 0.6 dB versus 25.2 ± 0.9 dB on nonaffected retinal areas (p < 0.001). Sensitivity was also decreased on µP2: 23.7 ± 0.2 dB for areas overlying the nevi and 25.7 ± 0.3 dB for the nonaffected retina (p < 0.001). mfERG responses showed no focal amplitude or implicit-time changes on the retina in the topographical region corresponding to the nevus for all patients.

Conclusion: Our results indicate that choroidal nevi may cause significant retinal sensitivity impairment, as shown by microperimetry, but preserved mfERG response indicates that the retinal function may be only partially impaired.