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[Grading of light perception and hand movement utilizing a novel device called the low vision evaluator]
H Kunikata1, Y Nakagawa, M Tsunoda
1Department of Ophthalmology, Tohoku University School of Medicine, 1-1 Seiryou-machi, Aoba-ku, Sendai 980-8574, Japan.
Purpose:
There has been no device for grading very low visual function expressed as light perception or hand movement up to the present. It is necessary to evaluate even slight effects of modern and classical therapies during the follow-up period. The goal of this study was to invent a novel device for grading such low visual function.
Methods:
Sixty-two patients with a visual acuity of counting fingers or worse due to various diseases were examined. The device, which we call the Low Vision Evaluator, has a pair of goggles equipped with two white light-emitting diodes. Nine variations of stimulus for light intensity (1, 10, 100 cd/m2 or 10, 100, 1,000 cd/m2) and duration (0.1, 0.3, 1 second) can be delivered in a random sequence. Patients were asked to push a button whenever they saw a stimulus. Response of patients to the stimuli was recorded.
Results And Conclusions:
The visual function of light perception and hand movement could be reproducibly assessed by this method. The method represents a valuable new tool for evaluating low visual function.