Spectral-Domain Optical Coherence Tomography Morphological Characteristics in Patients with Cone Dysfunction Disorders: A Retrospective Case Series.

PURPOSE: To describe spectral-domain optical coherence tomography (SD-OCT) morphological characteristics in patients with cone dysfunction disorders.

METHODS

This retrospective, single-center observational study was conducted at a tertiary referral university eye hospital between July 2018 and September 2020. Forty-two patients (84 eyes) with cone dysfunction disorders, diagnosed based on clinical findings and electroretinogram evidence of severely reduced or non-recordable cone responses with preserved rod function, were included in our study. SD-OCT imaging was performed, and images were evaluated regarding the integrity and pattern of hyper-reflective outer retinal bands. The relationship between these findings, age, central retinal thickness (CRT), and best-corrected visual acuity (BCVA) was assessed.

RESULTS

SD-OCT images of 82 eyes showed outer retinal abnormalities. Five SD-OCT morphological categories were found, including outer retinal atrophy (24.4%), poorly delineated outer retinal bands (22.0%), ellipsoid zone (EZ) disruption (19.5%), outer foveal defect (17.1%), and prominent outer retinal layers (17.1%). Additionally, five isolated OCT findings were detected, including foveal hypoplasia (14.6%), trans-retinal hyperreflective dots (THD) (29.3%), outer plexiform layer (OPL) schisis (11.0%), subretinal drusenoid-like deposits (9.8%), and EZ bowing (13.4%). Age and CRT were significantly different across the morphological categories (p<0.001). Eyes with prominent outer retinal layers had the best visual acuity, whereas those with outer retinal atrophy had the worst visual acuity; however, differences in BCVA among the morphological categories were not statistically significant in the univariate GEE analysis (p = 0.09) or after multivariable adjustment (p = 0.32).

CONCLUSION

SD-OCT imaging demonstrates diverse outer retinal morphological patterns in patients with cone dysfunction disorders. These patterns were associated with age and CRT but were not significantly associated with BCVA. The proposed morphological classification may help characterize disease morphology and warrants prospective evaluation in longitudinal, genetically characterized cohorts to determine its potential utility as a biomarker.