Determining Optimal Test Parameters for Assessing Dark Adaptation in People With Intermediate Age-Related Macular Degeneration

Abstract

Citation: Binns AM, Taylor DJ, Edwards LA, Crabb DP. Determining optimal test parameters for assessing dark adaptation in people with intermediate age-related macular degeneration. Invest Ophthalmol Vis Sci. 2018;59:AMD114-AMD121. https:// doi.org/10.1167/iovs.18-24211 PURPOSE. The primary aim was to determine optimal test conditions for evaluating dark adaptation in intermediate age-related macular degeneration (iAMD) in order to minimize test time while maintaining diagnostic sensitivity.METHODS. People with AMD and age-similar controls were recruited (aged >55 years). Rod intercept time (RIT) was assessed after a 76%, 70%, and 65% rhodopsin bleach at 58 eccentricity and 76% and 70% bleach at 128. Test order was randomized and a 30-minute washout period added between tests. Results were compared between control and iAMD groups and receiver operating characteristics (ROC) curves were constructed. RESULTS.A total of 26 participants with variable grades of macular health attended for two visits. There was a statistically significant difference in average RIT between the control and iAMD groups at 58 (median, IQR controls ¼ 5.8 minutes, 3.8-7.5; iAMD ¼ 20.6 minutes, 11.1-30.0; Mann-Whitney, P ¼ 0.01) and at 128 (mean, controls: 4.54 minutes 6 2.12 SD, iAMD ¼ 7.72 minutes 6 3.37 SD; independent samples t-test, P ¼ 0.03) following a 76% bleach. Area under the ROC curves was 0.83 (confidence interval [CI]: 0.64-1.0) and 0.79 (CI: 0.59-0.99) for these two test conditions, respectively. Five participants (45%) in the iAMD group had RITs >20 minutes for 76% bleach at 58, but none for any other test condition.CONCLUSIONS. Nearly half of the participants with iAMD produced unacceptably long recovery times (>20 minutes) using a 76% bleach at 58 eccentricity. The 76% bleach at 128 provided almost equivalent separation between AMD and controls but recovery was achieved within 20 minutes.

Response to ‘Comment on: ‘You have got dry macular degeneration, end of story’: a qualitative study into the experience of living with non-neovascular age-related macular degeneration’

“…Informal caregivers in wet AMD report a substantial psychological burden [ 4 , 5 ] and we speculate that this is likely the case for caregivers of individuals with dry AMD, and that these individuals (described as ‘the hidden patients’) also require support. We also agree that referral to low-vision services should not just be for those with severe visual disability; our previous work [ 6 – 8 ] has shown that the performance of tasks relating to everyday visual function may be affected in some patients with intermediate AMD whilst visual acuity remains relatively preserved. Moreover, the subtle visual symptoms of AMD are often misunderstood [ 9 ].…”

Longitudinal Assessment of Rod Function in Intermediate Age-Related Macular Degeneration With and Without Reticular Pseudodrusen

“…Our findings on the RIT are consistent with the previous studies, that the peripheral macula area had a shorter RIT than the central area. Binns et al 42 found the RIT at 128 eccentricity had a faster recovery than the 58 eccentricity in AMD group after exposed to 76% photobleach. A greater rod dysfunction at the paracentral macula has also been reported in the earlier studies by Flynn 13 and Pfau et al 43 When evaluating the RIT in our 30-minute testing protocol, we still found a large proportion of testing points in the RPD group that did not reach the rod intercept level after 30 minutes of dark adaptation.…”

Visual Function and Macular Carotenoid Changes in Eyes with Retinal Drusen—An Open Label Randomized Controlled Trial to Compare a Micronized Lipid-Based Carotenoid Liquid Supplementation and AREDS-2 Formula

“…Details about the testing procedure and device methodology have been previously described in detail elsewhere [36][37][38][39][40]. Briefly, measurements were performed in a darkened room with the chin stabilized on a rest, fully dilated pupils and under monocular viewing conditions [36][37][38][39][40]. Testing begins with photo-bleaching using a wavelength of 505 nm to pre-condition the retina into a photobleached state and subjects were instructed to fixate on a target light (635 nm).…”

“…Subsequently, a stimulus wavelength of 505 nm was presented at a fixed location and, using a 3-down/1-up modified staircase estimate design, and threshold was determined. Subjects were instructed to respond via a handheld response button when the stimulus was visible [37][38][39][40][41]. Upon completion, threshold values were reported as patient visual sensitivity units (dB) as a function of time, subsequent to the initial exposure, defined as the Rod Intercept Time [36][37][38][39][40].…”