The Impact of Supplemental Antioxidants on Visual Function in Nonadvanced Age-Related Macular Degeneration: A Head-to-Head Randomized Clinical Trial.
What this study found
Both antioxidant/carotenoid regimens improved macular pigment and several measures of visual function over 24 months, but adding mesozeaxanthin did not confer extra benefit over the AREDS2-based formulation. For the primary outcome, letter contrast sensitivity at 6 cycles per degree increased slightly in both groups (1.53 to 1.57 and 1.58 to 1.61), with a significant time effect (P = 0.013) and no between-group difference (time-by-group P = 0.881). Several secondary outcomes also improved over time, including contrast sensitivity at other frequencies, mesopic and photopic measures,…
- Study & population
- This was a 2-year head-to-head randomized clinical trial in adults with nonadvanced age-related macular degeneration conducted in Waterford, Ireland.
- Intervention
- Adults with nonadvanced age-related macular degeneration received one of two oral antioxidant/carotenoid regimens daily for 24 months.
- Key limitation
- The active-arm sample sizes were modest and the trial was single-center, which limits precision and generalizability.
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Open PDFOriginal abstract
Purpose The purpose of this study was to evaluate the impact of supplemental macular carotenoids (including versus not including meso-zeaxanthin) in combination with coantioxidants on visual function in patients with nonadvanced age-related macular degeneration. Methods In this study, 121 participants were randomly assigned to group 1 (Age-Related Eye Disease Study 2 formulation with a low dose [25 mg] of zinc and an addition of 10 mg meso-zeaxanthin; n = 60) or group 2 (Age-Related Eye Disease Study 2 formulation with a low dose [25 mg] of zinc; n = 61). Visual function was assessed using best-corrected visual acuity, contrast sensitivity (CS), glare disability, retinal straylight, photostress recovery time, reading performance, and the National Eye Institute Visual Function Questionnaire-25. Macular pigment was measured using customized heterochromatic flicker photometry. Results There was a statistically significant improvement in the primary outcome measure (letter CS at 6 cycles per degree [6 cpd]) over time (P = 0.013), and this observed improvement was statistically comparable between interventions (P = 0.881). Statistically significant improvements in several secondary outcome visual function measures (letter CS at 1.2 and 2.4 cpd; mesopic and photopic CS at all spatial frequencies; mesopic glare disability at 1.5, 3, and 6 cpd; photopic glare disability at 1.5, 3, 6, and 12 cpd; photostress recovery time; retinal straylight; mean and maximum reading speed) were also observed over time (P < 0.05, for all), and were statistically comparable between interventions (P > 0.05, for all). Statistically significant increases in macular pigment at all eccentricities were observed over time (P < 0.0005, for all), and the degree of augmentation was statistically comparable between interventions (P > 0.05). Conclusions Antioxidant supplementation in patients with nonadvanced age-related macular degeneration results in significant increases in macular pigment and improvements in CS and other measures of visual function. (Clinical trial, http://www.isrctn.com/ISRCTN13894787).