Abstract
Purpose: :
Best-corrected distance visual acuity (BCVA) currently serves as the main outcome measure for large multicenter trials in order to judge a new drugs efficacy. However there is a remarkable discrepancy between patient reported visual function and BCVA. The present study attempts to identify more accurate markers for visual function in neovascular AMD
Methods: :
Sixty-two treatment naïve patients received monthly intravitreal anti-VEGF for one year. Examinations occurred monthly and comprised fundus-controlled microperimetry using the NIDEK MP-1, reading performance (i.e. reading acuity and reading speed using the Radner reading charts), BCVA using ETDRS charts and contrast sensitivity using Pelli-Robson charts. In terms of microperimetry stimulation loci representing an absolute scotoma (0 dB) were counted. Loci with a sensitivity of 1 to 6 dB were considered dense relative scotoma and between 7-12 dB mild relative scotoma. Values above 13dB were considered normal.
Results: :
At baseline, 10.3±3.6 stimulation loci (of 33 total) were considered as absolute scotoma, dense or mild relative scotoma was evident in 6.8±1.8 and 8.6±2.3 stimulation loci, respectively. 7.2±2.9 loci were considered normal. One day after the first anti-VEGF dose, no statistically significant increase in any visual function parameter could be noted. Reading acuity at baseline was 0.72±0.1 logRAD, and showed the best score after 6 months (0.38±0.1 logRAD). BCVA improved from 0.57±0.09 to 0.19±0.05 after 11 months. Contrast sensitivity took even longer and improved from 1.09±0.06 at baseline to 1.37±0.05 after 12 months.The various parameters of visual function showed a characteristic pattern of recovery: logMAR increased significantly at month 1 following initial anti-VEGF (p<0.00001), whereas logRAD increased at month 2 and contrast sensitivity was increased significantly at month 3(p<0.007). Absolute scotoma size did not decrease significantly. Dense scotoma size decreased significantly after 4 months (p<0.022) with a concomitant increase of sites of normal retinal function as early as 2 months after baseline (p<0.016).
Conclusions: :
While the mere consideration of BCVA might suggest quick and satisfying visual recovery, a more detailed evaluation of visual function reveals possible explanations for patient experienced visual impairment.
Keywords: age-related macular degeneration • retinal neovascularization • macula/fovea