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Michael Boland, Pradeep Ramulu, Karun Arora, Joan Jefferys, David Friedman; A quantitative approach to the analysis of visual field defect location and its relationship to measures of disability. Invest. Ophthalmol. Vis. Sci. 2013;54(15):4015. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To determine, using a quantitative method, whether the location of visual field loss is related to measures of disability
The Salisbury Eye Evaluation was a population-based study of elderly residents of Salisbury, Maryland. Participants underwent visual field (VF) testing and were evaluated for measures of disability including driving status, reading speed, mobility course speed, walking speed, stair climbing rate, and the Activities of Daily Vision Scale (ADVS.) Between 409 and 487 participants with some VF loss completed measures of disability and bilateral VF testing. As a quantitative measure of the distribution of VF, we calculated the first order moment of the linear scale threshold values from an integrated binocular VF. This moment is analogous to the center of mass of a physical object. To more completely capture the distribution of vision, we calculated the second and third order central moments of the linearized threshold values. These values are comparable to the concepts of variance and skewness in statistics. All three moments were calculated along both the vertical and horizontal axes of the VF. Logistic and log-linear models were used to assess the relationship between the moments and the measures of disability.
Using the first order moment along the vertical axis as a measure of inferior v. superior vision loss, the likelihood of not driving (OR 1.59, CI 1.15 to 2.20), scoring 79 or less on the ADVS (OR 2.11, CI 1.40 3.18), or reading ≤ 90 words per minute (OR 1.40, CI 1.07 to 1.83) were all worse with inferior VF loss (center of remaining VF shifted superior) as compared to superior VF loss. Reading speed declined by 10.7 words per minute (CI -16.7 to -4.6) for each degree the center of remaining vision was displaced upward by inferior VF loss. Using the second order moment along the horizontal axis as a measure of central v. peripheral VF loss, the risk of not driving, of scoring poorly on the ADVS, and reading speed were all worse with both central and peripheral vision loss but only reading speed was significantly more affected by central vision loss.
A set of objective, quantitative measures of the location of VF loss show that while multiple measures of disability are affected by the location of vision loss in the vertical direction, only reading speed is significantly more affected by inferior VF loss.
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