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David Neely, Anna V Zarubina, Mark E Clark, Carrie E Huisingh, Gregory R Jackson, Gerald McGwin, Christine A Curcio, Cynthia Owsley; Association between subretinal drusenoid deposits (SDD) seen by multimodal imaging and dark adaptation (DA) in normal, early, and intermediate age-related macular degeneration (AMD) eyes. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2777. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Delayed rod-mediated DA is characteristic of early AMD and some older adults in normal macular health. The delay is attributed to poor retinoid translocation from choriocapillaris to photoreceptors due to a physical barrier in aged Bruch’s membrane and unknown factors in RPE. SDD are extracellular lesions that confer risk for AMD progression independently from drusen. SDD may impose a further barrier in the subretinal space plus inflict direct toxicity on cells. We examined the association between SDD identified by multimodal retinal imaging and DA in older eyes in normal macular health or with early or intermediate AMD.
Subjects enrolled in the Alabama Study on Age-Related Macular Degeneration (ALSTAR) study were assessed for the presence of SDD using color fundus photos, IR and AF images, and SD-OCT volumes (Zarubina et al. abstract submitted). AMD severity was determined using the AREDS 9-step scale for color fundus photographs. Rod-mediated DA was measured for one eye of each subject following a photobleach using a computer-automated dark adaptometer with targets centered at 5° on the superior retinal vertical meridian; thresholds were measured for 20 minutes post-bleach. Speed of DA was characterized by the rod-intercept, defined as the duration (minutes) required for sensitivity to recover to a criterion value that is in the latter half of the second component of rod recovery.
Both multimodal SDD identification and DA testing were completed on one eye of 547 participants aged 60-92 years old (Mean age 69). Of these 76% were in normal macular health, 23% had early AMD, and 2% intermediate AMD. For the total sample, mean rod intercept was greater for eyes with SDD (n=139) vs. no SDD (n=408) (M 14.9 vs. 11.4 min, p<0.0001, age-adjusted p=0.002). For those with AMD, eyes with SDD (n=69) had greater rod-intercepts than those without SDD (n=65) (M 17.2 vs. 12.7 min, p=0.017, age-adjusted p=0.098; Figure). For normal eyes, the rod-intercept did not differ between eyes with (N=70) and without SDD (N=343) (M 11.6 vs. 11.1 min, p=0.49, age-adjusted p=0.993).
Findings suggest that SDD as determined by multimodal imaging in AMD is associated with slowed rod-mediated DA as compared to those AMD eyes without SDD.
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