Abstract
Purpose :
Studies suggest delayed rod-mediated dark adaptation (DA) is a diagnostic indicator of age-related macular degeneration (AMD). We assessed if DA differences (estimated by rod-intercept time [RIT]) are more discernible between AMD severity grades using an OCT-based criteria (including subretinal drusenoid deposit [SDD] presence) over a Colour Fundus Photography (CFP)-based classification.
Methods :
Data was acquired from two related cross-sectional population based studies - Northern Ireland Sensory Aging studies (NISA;NISA-2). Participants with RIT data (AdaptDx [Maculogix,USA]) and both CFP (Canon CX-1 Digital Fundus Camera [Canon,USA]) and spectral domain OCT (SD-OCT;Heidelberg Spectralis SD-OCT [Heidelberg Engineering, Germany]) images were used. SDD presence was identified and images graded by Beckman and OCT-based classifications. Age-corrected time-to-event analysis assessed the magnitude of differences in RIT and plotted using Kaplan Meier curves (Fig 1).
Results :
459 eyes (mean [standard deviation; SD] age 66[8] years) were stratified into Beckman0-3 and then OCT0-2. Uncorrected mean(SD) RIT for Beckman groups was 7.5(5.3), 8.0(4.3), 7.3(4.7) and 15.6(11.9) mins, respectively. Uncorrected mean(SD) RIT for OCT groups appeared more distinct between gradings: 7.4(5.5), 10.0(7.2) and 15.3(21.0) mins respectively. After age-correcting, eyes in B3 had statistically significantly worse average RITs compared to the other groups (B0-2; p=<0.005 all) but there were no differences in RIT between the other Beckman groups. Eyes in OCT2 had worse RITs compared to controls (OCT0) (p=<0.001) and eyes in OCT1 (p=0.009). No statistically significant difference was found between OCT0 and OCT1 (p=0.195). SDD presence significantly worsened RIT within OCT2 (p=0.002) but not within OCT1 (p=0.285). In OCT0 the presence of SDDs gave better RIT values(p=0.012).
Conclusions :
There is some evidence of differences in RIT being more apparent between AMD severity grades using an OCT-based rather than a CFP-based classification, but differences were less clear once corrected for age. OCT classifications including SDDs, may be useful for clinical trials in AMD. A highlight of our enriched population study is a uniquely large SDD sample (n=109) not regularly reported in recent DA research.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.