Abstract
Purpose :
We have previously developed a method of simulating a central scotoma, as found in age-related macular degeneration (AMD), using centrally-opaque contact lenses (CLs). The aim of this study was to determine how realistic our AMD simulation was of real AMD by comparing the street-crossing decision-making performance of subjects with real AMD to those with simulated AMD using our simulation tool.
Methods :
Street-crossing decisions along a non-signalized, one-way street were collected in 17 AMD subjects with a scotoma, 34 AMD subjects without a scotoma and 20 normally-sighted subjects wearing centrally-opaque CLs that induced a central scotoma. Subjects observed approaching traffic for a two second period after which they reported whether or not they believed that the vehicular gap time was long enough to afford a safe crossing. When subjects indicated that they would cross when the measured vehicular gap time was shorter in duration than their actual crossing time, this was considered an unsafe decision. When subjects indicated that they would not cross when the measured vehicular gap time was longer in duration than their actual crossing time, this was considered a missed decision. For each subject, the percentage of unsafe (%unsafe) and missed (%missed) decisions were calculated. A generalized linear mixed model with binary logistic function, repeated measures for subject and a covariate to adjust for age differences was used to determine if the %unsafe and %missed decisions changed as a function of subject group (AMD with a scotoma versus AMD with no scotoma versus simulated AMD with a scotoma).
Results :
The simulated AMD subjects made as many %unsafe and %missed decisions as those with real AMD with a scotoma (p=0.98 and p=0.66 for %unsafe and %missed, respectively) and without a scotoma (p=0.19 and p=0.13 for %unsafe and %missed, respectively). While those AMD subjects with no scotoma made as many %missed decisions as AMD subjects with a scotoma (p=0.26), they did have a tendency to make more %unsafe decisions (p=0.09).
Conclusions :
Our method of AMD simulation appears to mimic the street-crossing decision-making performance of people with real AMD. This simulation tool may therefore be beneficial to future studies assessing the functional performance of people with AMD.
This is a 2021 ARVO Annual Meeting abstract.