Abstract
Purpose: :
To assess visual acuity (VA) loss as a risk factor for advanced AMD in Age-Related Eye Disease Study (AREDS) participants with either bilateral drusen or unilateral AAMD at baseline.
Methods: :
Logistic regression was used to assess the association of VA loss from baseline prior to the development of advanced AMD (choroidal neovascularization (CNV) or central geographic atrophy (CGA)). We studied 2352 AREDS participants with bilateral drusen (randomly chosen eye) and 707 participants with unilateral AMD (end stage AMD in the fellow eye at baseline). Best-corrected VA in AREDS was measured using a standardized ETDRS protocol. VA change from baseline was treated as a continuous variable. We calculated the odds of developing various forms of AAMD for 1-4, 5-9, 10-14, and 15+ letters of VA loss from the logistic regression beta coefficients. Models were adjusted for covariates including age, gender, smoking status and severity of ocular risk factors (drusen area, maximum drusen size, and pigment abnormalities). We used a risk analysis to demonstrate the 5-year risk of AAMD associated with various degrees of VA change.
Results: :
400 eyes of participants with bilateral drusen (17%), and 382 eyes of participants with unilateral AMD (54%) progressed to AAMD during 8.2 years follow-up (mean). Change in VA from baseline was associated with an increased risk of progression to AAMD (p-value < 0.0001). For participants with bilateral drusen the adjusted odds for 1-4, 5-9, 10-14 and 15+ letters of VA loss from baseline were 1.08, 1.44, 2.07 and 2.97, respectively. The adjusted odds for the same degree of letter loss for participants with unilateral AAMD were 1.06, 1.35, 1.83, and 2.48.For participants with unilateral AAMD losing 1-4 letters, the five-year risk of developing CNV was 21.8% compared to 4.5% for those who did not lose 1-4 letters. For the bilateral group, the corresponding five-year CNV risks were 4.9% vs. 1%. For participants with unilateral AAMD losing 5-9 letters, the five-year CNV risk was 45.7% compared to 26.3% for those who did not lose 5-9 letters. For the bilateral group, the corresponding five-year CNV risks were 6.4% vs. 5.9%. Similar results were found for CGA and AAMD in general.
Conclusions: :
In patients with either bilateral drusen or unilateral advanced AMD, a drop in visual acuity over time is an important risk factor for the development of CNV, CGA, and AAMD in general.
Clinical Trial: :
www.clinicaltrials.gov NCT00000145
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • choroid: neovascularization • visual acuity