Correlation of Dark Adaptation with Macular Morphology in Age-related Macular Degeneration

Abstract

Purpose : There is increasing evidence that Dark-adaptation (DA) is a useful functional parameter for both detection and severity of AMD. However, the relationship between DA and macular structural changes in AMD has not been well studied. This study aims to evaluate the correlation between DA and morphology using spectral-domain optical coherence tomography (SD-OCT) in the area bleached during the DA testing and in the entire macula

Methods :
Cross-sectional, prospective study, including patients with AMD and a control group (> 50 years) without any vitreoretinal disease. All participants were imaged with color fundus photographs and SD-OCT. Both eyes were tested with the AdaptDx® DA extended protocol (20 minutes). A software program was developed to map the DA testing spot (5 degree superior to fovea) on the OCT B-scans. Two independent graders evaluated the B-scans’ regions included in this spot, as well as in the entire macula, and recorded the presence of several AMD-associated abnormalities. Multilevel mixed effect linear models (accounting for correlated outcomes between 2 eyes) were used for analyses, considering rod-intercept time (RIT) as the outcome

Results : We included 137 eyes (n=77 subjects), 72.3% with AMD and the remaining controls. OCT structural abnormalities were observed within the DA testing spot in 44.5% of the eyes, and in the entire macula in 71.5% . Multivariate analysis revealed that adjusting for age and AMD stage, the presence of any abnormalities within the DA testing spot (ß=4.8, p<0.001), as well as in the macula (ß=2.4, p=0.047), were significantly associated with delayed RITs. In eyes with no structural changes within the DA testing spot (n=76, 55.5%), pathology in the remaining macula was associated with impaired RITs (ß=2.00, p=0.046). The presence of subretinal drusenoid deposits was a consistent predictor of RIT, both if located within the DA spot (ß=3.51, p=0.001), or the macula in general (ß=3.19, p<0.001). Within the testing spot, the presence of ellipsoid disruption, classic drusen and serous PED were also significantly associated with impairments in DA (p≤0.018).

Conclusions : Our results suggest a strong association between retinal anatomy evaluated by OCT and time to dark-adapt. Dark-adaptation is a good indicator of abnormality in the entire macula and not just within the testing spot. Subretinal drusenoid deposits appear to significantly affect dark adaptation.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.