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

Binns, A. M. ORCID: 0000-0001-8621-498X, Taylor, D. J., Edwards, L. A. and Crabb, D. P. ORCID: 0000-0001-8754-3902 (2018). Determining Optimal Test Parameters for Assessing Dark Adaptation in People With Intermediate Age-Related Macular Degeneration. Investigative Ophthalmology & Visual Science, 59(4), pp. 114-121. doi: 10.1167/iovs.18-24211

Abstract

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 5° eccentricity and 76% and 70% bleach at 12°. 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 5° (median, IQR controls = 5.8 minutes, 3.8–7.5; iAMD = 20.6 minutes, 11.1–30.0; Mann-Whitney, P = 0.01) and at 12° (mean, controls: 4.54 minutes ± 2.12 SD, iAMD = 7.72 minutes ± 3.37 SD; independent samples t-test, P = 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 5°, 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 5° eccentricity. The 76% bleach at 12° provided almost equivalent separation between AMD and controls but recovery was achieved within 20 minutes.

Publication Type: Article
Publisher Keywords: dark adaptation, age-related macular degeneration, rod intercept time
Subjects: R Medicine > RE Ophthalmology
Departments: School of Health Sciences > Optometry & Visual Science
URI: http://openaccess.city.ac.uk/id/eprint/20465
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