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Cone photoreceptor macular function and recovery after photostress in early non-exudative age-related macular degeneration

Authors Rodriguez JD, Lane K, Hollander DA, Shapiro A, Saigal S, Hertsenberg AJ, Wallstrom G, Narayanan D, Angjeli E, Abelson MB

Received 15 February 2018

Accepted for publication 5 April 2018

Published 27 July 2018 Volume 2018:12 Pages 1325—1335


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Scott Fraser

John D Rodriguez,1 Keith Lane,1 David A Hollander,1,2 Aron Shapiro,1 Sunita Saigal,1 Andrew J Hertsenberg,1 Garrick Wallstrom,3 Divya Narayanan,1 Endri Angjeli,1 Mark B Abelson1,4

1Ora, Inc., Andover, MA, USA; 2Jules Stein Eye Institute, University of California, Los Angeles, CA, USA; 3Statistics and Data Corporation, Tempe, AZ, USA; 4Department of Ophthalmology, Harvard Medical School, Boston, MA, USA

Purpose: To identify parameters from cone function and recovery after photostress that detect functional deficits in early non-exudative age-related macular degeneration (AMD) and to determine the repeatability of these parameters.
Methods: Cone-mediated visual function recovery after photostress was examined in three groups of subjects: young normal subjects (ages 20–29; N=8), older normal subjects (ages 50–90; N=9), and early non-exudative AMD subjects (ages 50–90; N=12). Eight AMD and four normal subjects were retested 1 year after the initial evaluation. Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity (VA) and parameters of cone function (baseline cone sensitivity and cone recovery half-life following photobleach) were measured and compared between AMD and normal subjects. Short-term repeatability was assessed for each subject’s initial evaluation. Long-term repeatability was assessed by comparing outcomes from the initial evaluation and 1-year follow-up.
Results: The mean baseline cone threshold was significantly worse in subjects with early AMD compared to older normal subjects (-1.80±0.04 vs -1.57±0.06 log cd/m2 p=0.0027). Moreover, the baseline cone threshold parameter exhibited good short-term (intraclass correlation coefficient [ICC]=0.88) and long-term (ICC=0.85) repeatability in all subjects. The cone intercept parameter and ETDRS VA were not significantly different between AMD and older normal subject groups. Cone recovery half-life was significantly different between older normal and AMD subject groups (p=0.041). Neither ETDRS VA nor cone function parameters were significantly different for any group at the 1-year follow-up.
Conclusion: The baseline cone threshold shows potential as a novel parameter to assess visual dysfunction in early AMD. This outcome consistently detected deficits in AMD subjects, and differentiated them from age-matched controls with high test–retest repeatability.

Keywords: AMD, photobleach, photoreceptor, cone recovery, Ora LUX

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