Choroidal Melanocytosis Evaluation with Enhanced Depth Imaging Optical Coherence Tomography

Abstract

To assess eyes with unilateral choroidal melanocytosis using enhanced depth imaging (EDI) optical coherence tomography (OCT). Retrospective, observational case series. Fifteen patients with unilateral choroidal melanocytosis. Each patient was evaluated with EDI-OCT, and comparison was made of involved versus uninvolved foveal retinal and choroidal layers. Enhanced depth imaging OCT features of choroidal melanocytosis. The mean patient age was 28 years (median, 23 years; range, 5-76 years). There were 9 male and 6 female patients. Best-corrected visual acuity ranged from 20/20 to 20/30. All patients had subfoveal involvement with choroidal melanocytosis. Associated features included dermal (n= 6), scleral (n= 9), iris (n= 3), and palate (n= 1) melanocytosis. Spectral domain EDI-OCT revealed normal inner retina (n= 15) and normal outer retina (n= 14). The only retinal abnormality was a defect in both the myoid zone and the ellipsoid junction (n= 1). The affected choroid showed smooth anterior contour (n= 15) and thinned or compressed choriocapillaris (n= 2), thinned (n= 3) or thickened (n= 3) medium vessels, and thinned large vessels (n= 2). The subfoveal choroid was a mean 23% thicker in the involved eye, with a mean thickness of 326.4 μm (median, 326 μm; range, 120-459 μm) compared with 264.4 μm (median, 260 μm; range, 94-462 μm) in the uninvolved eye (P= 0.15). The choroidal perivascular interstitial tissue was 51% thicker in the study eye, enwrapping and silhouetting the medium and large vessels (P= 0.01). The ratio between the perivascular stromal tissue and the subfoveal choroidal thickness was 66% in the study eye and 54% in the normal eye (P= 0.0001). Deep partial (n= 5) or complete (n= 2) tissue shadowing was noted. Enhanced depth imaging OCT revealed that choroidal melanocytosis shows increased subfoveal choroidal thickness with an apparent increase in the choroidal perivascular stromal tissue and minimal effect on the overlying retina.