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Han Li, Susan Culican; Screening for AMD Using Psychophysical Correlates of Macular Dysfunction. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5022. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the utility of our novel computerized vision task as a screening tool for AMD and other macular disorders.
We developed a computerized task and administered it to 20 participants with AMD or other macular disorders, and 17 similarly aged control participants. The task was based on participant identification of interruptions in visual stimuli. Testing was conducted monocularly. Subject distance to the video display was determined by empirical adjustment, by positioning the physiological blind spot at the periphery of stimuli. Stimuli consisted of a central fixation point surrounded by rotating objects. Objective interruptions of some objects were programmed into the stimuli, which the participant was instructed to report by striking a key. We hypothesized that those with macular dysfunction would subjectively perceive more interruptions than were programmed, due to foveal and parafoveal scotomata.
Our results show significantly different task performance between those with and without macular disorders. Macular disorder participants reported a higher number of subjective interruptions (n=4.65 vs n=0.35, p<.001) as well as total errors, defined as sum of missed objective interruptions and subjective interruptions, compared to controls (n=6.3 vs n=1.24, p<.001). There was no significant difference in the number of missed objective interruptions alone (n=1.65 vs n=0.88, p=.158). Disease status correlates with test performance, while controlling for near distance visual acuity (p=.001). Furthermore, interocular test performance was the same in control participants, with no significant difference in subjective interruptions, missed objective interruptions, and total errors.
Our visual task discriminates between macular disorder and control group participants, independent of visual acuity. Participant attention and instruction compliance were high, while fatigue and interocular learning curve effects were negligible. These results suggest that our novel computer task could be used as a rapid and effective screening tool in detecting macular disorder. In particular, the number of subjective interruptions could be used as a reliable screening parameter. However, further testing in demonstrating reliability and validity of our results must be done.
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