Visual factors and mobility in persons with age-related macular degeneration.

The objectives of this study were to determine the effects of reducing light level on mobility performance in persons with age-related macular degeneration (ARMD) and how performance relates to measures of visual sensory and perceptual function. ARMD results in the loss of central, high-acuity vision and is the leading cause of vision loss in veterans participating in the blind rehabilitation programs of the Department of Veterans Affairs. In 41 subjects with ARMD acuity, peak letter contrast sensitivity, visual field extent, glare disability, color confusion, spatio-temporal contrast sensitivity, motion sensitivity, scanning ability, and figure-ground discrimination were measured to determine their ability to predict mobility performance. Mobility performance was assessed under photopic (high illumination) and mesopic (low illumination) lighting conditions on a laboratory obstacle course and two real-world courses, an indoor hallway and an outdoor residential route. Reducing illumination resulted in significant increases in the time to complete each course and the number of mobility incidents (errors) that occurred. Two measures of overall performance, total time and total mobility incidents, were calculated for each course by summing time and incidents over the two illumination levels. Combinations of vision variables were able to account for 30 to 60% of the variance in the measures of overall performance. Log contrast sensitivity measured with the Pelli-Robson chart test and visual field extent were the most important predictors of performance. Other variables making significant contributions to prediction in multi-predictor models included: scanning ability, glare sensitivity, color confusion, and peak contrast sensitivity to drifting gratings.

[1]  I L Bailey,et al.  New Design Principles for Visual Acuity Letter Charts* , 1976, American journal of optometry and physiological optics.

[2]  R. Burdett,et al.  Contrast sensitivity function and mobility in elderly patients with macular degeneration. , 1989, Journal of the American Optometric Association.

[3]  I L Bailey,et al.  Effect of Luminance, Contrast, and Eccentricity on Visual Acuity in Senile Macular Degeneration , 1984, American journal of optometry and physiological optics.

[4]  M. Bullimore,et al.  Assessing the reliability, discriminative ability, and validity of disability glare tests. , 1993, Investigative ophthalmology & visual science.

[5]  A. Adams,et al.  Early color vision changes in age-related maculopathy. , 1987, Applied optics.

[6]  R C Kleiner,et al.  Contrast sensitivity in age-related macular degeneration. , 1988, Archives of ophthalmology.

[7]  Denis G. Pelli,et al.  THE DESIGN OF A NEW LETTER CHART FOR MEASURING CONTRAST SENSITIVITY , 1988 .

[8]  B Brown,et al.  Contribution of Vision Variables to Mobility in Age‐Related Maculopathy Patients , 1986, American journal of optometry and physiological optics.

[9]  K. Turano,et al.  Traditional Measures of Mobility Performance and Retinitis Pigmentosa , 1998, Optometry and vision science : official publication of the American Academy of Optometry.

[10]  J. L. Elliott,et al.  Visual Correlates of Obstacle Avoidance in Adults with Low Vision , 1998, Optometry and vision science : official publication of the American Academy of Optometry.

[11]  M. Frostig,et al.  Administration and scoring manual for the Marianne Frostig Developmental Test of Visual Perception , 1966 .

[12]  R. Sekuler,et al.  Contrast sensitivity throughout adulthood , 1982, Vision Research.

[13]  J. Lovie-Kitchin,et al.  What areas of of the visual field are important for mobility in low vision patients , 1990 .

[14]  S. Haymes,et al.  Mobility of People with Retinitis Pigmentosa as a Function of Vision and Psychological Variables , 1996, Optometry and vision science : official publication of the American Academy of Optometry.

[15]  J. L. Elliott,et al.  Visual Correlates of Mobility in Real World Settings in Older Adults with Low Vision , 1998, Optometry and vision science : official publication of the American Academy of Optometry.

[16]  T. Kuyk,et al.  Environmental variables and mobility performance in adults with low vision. , 1996, Journal of the American Optometric Association.

[17]  B. Brown,et al.  Dark Adaptation and the Acuity/Luminance Response in Senile Macular Degeneration (SMD) , 1983, American journal of optometry and physiological optics.

[18]  I. Bailey,et al.  Visual Factors and Orientation‐Mobility Performance , 1982, American journal of optometry and physiological optics.

[19]  B. Brown,et al.  Effects of Luminance on Contrast Sensitivity in Senile Macular Degeneration , 1983, American journal of optometry and physiological optics.

[20]  D. Geruschat,et al.  Low Vision Mobility Problems: Perceptions of O&M Specialists and Persons with Low Vision , 1992 .

[21]  E.W. Hill,et al.  Mobility in Individuals with Moderate Visual Impairments , 1990 .

[22]  P E King-Smith,et al.  A quantitative scoring technique for panel tests of color vision. , 1988, Investigative ophthalmology & visual science.