Abstract
Purpose: :
To investigate the relationship between baseline psychophysical measures of visual function in age-related maculopathy (ARM) and the subsequent development of advanced visual loss from age-related macular degeneration.
Methods: :
36 participants (aged 52-85yrs) with early ARM and good acuity (≤ 0.3 logMAR) in the study eye and advanced AMD in the fellow eye underwent a battery of psychophysical tests at baseline examination (logMAR acuity, Pelli-Robson contrast sensitivity, photopic and scotopic interferometric acuity, achromatic and short-wavelength-sensitive (SWS) resolution acuity). Stereoscopic colour fundus photographs were graded using the Wisconsin Age-Related Maculopathy Grading System (WARMGS) and features of ARM were combined to assign a severity stage from 0 to 5 using the methods described by the Rotterdam Eye Study. Participants clinical records were examined for a period of up to 5 years from baseline, with participants being divided into two groups based on whether or not the study eye lost a significant amount of visual acuity (greater than 3 lines of logMAR acuity) in this follow-up period.
Results: :
8 participants suffered a significant drop in visual acuity during follow-up, while 26 participants did not. There was no significant difference in age (M=73.4 vs 71.9yrs; p=0.63) or follow-up time (M=34.2 vs 28.5mths; p=0.34) between these two groups. Achromatic and SWS resolution acuity were both significantly reduced at baseline in those subjects who developed a significant loss in visual acuity compared to those who did not (p<0.05). There was no significant difference in any of the other visual function measures between the two groups. ARM stage at baseline was the strongest predictor of disease progression, with a significant difference in the baseline ARM stage between those who lost a significant amount of visual acuity over this follow-up period and those who did not (Mann-Whitney U test, p=0.03).
Conclusions: :
This study has shown that although advancing ARM stage (stages 4, 5) was the strongest predictor of subsequent visual acuity loss in this group of participants, measures of achromatic and SWS resolution acuity in ARM have the potential to identify those most at risk of subsequently developing significant visual loss due to AMD. Larger longitudinal studies are required to fully investigate the relationships between ARM stage, visual function and the development of significant visual loss and end-stage disease.
Keywords: color vision • visual acuity • choroid: neovascularization