Spectral-domain optical coherence tomography morphological characteristics in patients with cone dystrophy

Abstract

Abstract Purpose: To describe spectral-domain optical coherence tomography (SD-OCT) morphological characteristics in patients with cone dystrophy. Methods: Forty-two patients (84 eyes) with the diagnosis of cone dystrophy based on clinical findings and electroretinogram reports (severely reduced or non-recordable cone response with preserved rod function) were included in our study. SD-OCT was performed and images were evaluated regarding the integrity and pattern of hyper-reflective outer retinal bands and other findings. The relationship between these findings, age, central subfoveal thickness (CST), and best-corrected visual acuity (BCVA) was assessed. Results: 82 of 84 eyes (98 %) showed outer retinal layer abnormalities on SD-OCT. Five different morphological categories were identified on SD-OCT, including outer retinal atrophy (24.4%), undifferentiated outer retinal layers (22.0%), ellipsoid zone (EZ) disruption (19.5%), outer foveal defect (17.1%), and prominent outer retinal layers (17.1%). Also, five isolated OCT findings were detected, including foveal hypoplasia (14.6%), trans-retinal hyperreflective dots (THD) (29.3%), outer plexiform layer (OPL) schisis (11.3%), pseudodrusen (9.8%), and EZ bowing (13.4%). Age and CST were significantly different across the morphological categories (p<0.001). Eyes with prominent outer retinal layers and outer retinal atrophy had the best and worst visual acuity, respectively; however, the difference was not significant (p=0.16). Conclusion: SD-OCT imaging shows variety of morphologic findings in cone dystrophy, which may be utilized in the assessment of these patients and may serve as predictive biomarkers for VA.