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A. C. Nau, C. Pintar, C. N. Fisher; A Standardized Obstacle Course for Low Vision Mobility Assessment. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3623.
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There are no widely accepted standards for determining whether a person with limited visual potential is at risk for a fall accident. We report the design of an obstacle course which will provide a quantifiable method of determining whether a person with low vision is able to successfully negotiate through their environment.
We created a portable obstacle course 40 feet long by 7 feet wide. Obstacles consist of 11 Styrofoam shapes that have been selected to represent objects encountered in everyday life. There are three versions, each designed to be harder to navigate. 10 obstacles are arranged in patterns of increasing difficulty with three iterations within each level to prevent memorization of the course. Subjects are evaluated in both dim and bright illuminaton allowing for six iterations of the course per level of difficulty for a total of 18 different course permutations. Each course takes 1-5 minutes to navigate, depending on level of skill and residual vision. Patients wear an accelerometer and all runs through the course are videotaped. A 30 second visual identification and detection task is administered for each level of difficulty.
Performance measures include: time to complete the course (walking speed), number of bumps, number of orientation errors, number of behavior changes (hesitations), differences in gait and sway. We can analyze with respect to illumination level, contrast and height of obstacles and floor texture. Additional analysis evaluates ability to detect and/or identify obstacles, which may or may not correlate with walking speed etc. Comparisons can also be made between baseline performance and post-mobility training performance. Pilot data suggests that within each level of difficulty, the three course variations are of equal difficulty. Results also indicate that there is a correlation between visual acuity and obstacle course performance.
There are currently no standardized measures in place for determining navigation abilities or fall risk of the visually impaired. This obstacle course provides such a measure. Insurance companies, researchers, low vision providers and regulatory agencies will be interested in this type of objective data as they continuously seek interventions that will reduce health care costs.
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