Delayed Rod-Mediated Dark Adaptation Is a Functional Biomarker for Incident Early Age-Related Macular Degeneration

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• 作者：Cynthia Owsley ; PhD¹ ; ^{owsley@uab.edu" class="auth_mail" title="E-mail the corresponding author} ; Gerald McGwin Jr. ; PhD¹ ; ² ; Mark E. Clark ; BS¹ ; Gregory R. Jackson ; PhD³ ; Michael A. Callahan ; MD¹ ; Lanning B. Kline ; MD¹ ; C. Douglas Witherspoon ; MD¹ ; Christine A. Curcio ; PhD¹
• 关键词：AMD ; age-related macular degeneration ; CI ; confidence interval ; DA ; dark adaptation ; GA ; geographic atrophy ; RPE ; retinal pigment epithelium ; RR ; risk ratio ; SD ; standard deviation ; SDD ; subretinal drusenoid deposit ; UAB ; University of Alabama at Birmingham
• 刊名：Ophthalmology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：123
• 期：2
• 页码：344-351
• 全文大小：620 K

文摘

To examine whether slowed rod-mediated dark adaptation (DA) in adults with normal macular health at baseline is associated with the incidence of age-related macular degeneration (AMD) 3 years later.

Design

Prospective cohort.

Participants

Adults aged ≥60 years were recruited from primary care ophthalmology clinics. Both eyes were required to be step 1 (normal) on the Age-Related Eye Disease Study 9-step AMD classification system based on color fundus photographs graded by experienced and masked evaluators.

Methods

Rod-mediated DA was assessed at baseline in 1 eye after a photobleach using a computerized dark adaptometer with targets centered at 5° on the inferior vertical meridian. Speed of DA was characterized by the rod-intercept value, with abnormal DA defined as rod-intercept ≥12.3 minutes. Demographic characteristics, best-corrected visual acuity, and smoking status were also assessed. Log-binomial regression was used to calculate unadjusted and adjusted risk ratios (RRs) and associated 95% confidence intervals (CIs) for the association between baseline DA and incident AMD.

Main Outcome Measures

Presence of AMD at the 3-year follow-up visit for the eye tested for DA at baseline.

Results

Both baseline and follow-up visits were completed by 325 persons (mean age, 67.8 years). At baseline, 263 participants had normal DA with mean rod-intercept of 9.1 (standard deviation [SD], 1.5), and 62 participants had abnormal DA with mean rod-intercept of 15.1 (SD, 4.0). After adjustment for age and smoking, those with abnormal DA in the tested eye at baseline were approximately 2 times more likely to have AMD in that eye (RR, 1.92; 95% CI, 1.03–3.62) by the time of the follow-up visit, compared with those who had normal DA at baseline.

Conclusions

Delayed rod-mediated DA in older adults with normal macular health is associated with incident early AMD 3 years later, and thus is a functional biomarker for early disease. The biological relevance of this test is high, because it assesses translocation of vitamin A derivatives across the retinal pigment epithelium and Bruch's membrane, 2 tissues with prominent age- and AMD-related pathology.