Abstract
Purpose:
To understand the effect of ranibizumab treatment on low luminance best-corrected visual acuity (BCVA) over 24 months in neovascular age-related macular degeneration (AMD) patients in the HARBOR study (NCT00891735).
Methods:
In the primary HARBOR study, patients were randomized 1:1:1:1 to receive intravitreal ranibizumab 0.5 mg or 2.0 mg monthly or PRN after 3 monthly loading doses. In this analysis, all 4 treatment groups were pooled (N=1084). Low luminance vision (LLVA) was measured by using a standard occluder over which a transparent, gray film (a 2.0-log-unit neutral density filter) is taped and having the patient read the normally illuminated ETDRS chart. Analysis of variance (ANOVA) was used for baseline comparisons of continuous outcomes among treatment groups. The relationship between BCVA and LLVA at baseline was analyzed by linear regression.
Results:
Mean BCVA at baseline was similar across all treatment groups (P=0.79), ranging from 53.6 to 54.5 letters. Mean LLVA at baseline was also similar across treatment groups (P=0.81), ranging from 28.2 to 29.3 letters. The minimum LLVA was 0 letters and the maximum LLVA ranged from 62-66 letters across treatment groups. Patients with better BCVA at baseline also generally had better LLVA at baseline (P<0.0001). For all treatment groups pooled, LLVA increased, on average, by 15.4 letters from baseline at Month 24, which was nearly twice as many letters as the mean gain in BCVA (8.7 letters). The mean BCVA change from baseline was generally stable between Months 3 to 24, while the mean LLVA increased by 3.3 letters from Month 3 to Month 24. A greater magnitude of LLVA gain from baseline is associated with greater BCVA gains from baseline.
Conclusions:
Low luminance vision improved nearly twice as much as normal luminance vision with ranibizumab for neovascular age-related macular degeneration. Patients who gained more low luminance vision also experienced a greater gain in normal luminance vision. Further correlations between low luminance testing in the clinic and patient functioning in daily activities require further study.