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A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision
Published on: February 11, 2014
Comparison of the visual function index to the Snellen Visual Acuity Test in predicting older adult self-restricted
Shahram Lotfipour1, Bhakti Harishchandra Patel, Thomas Aaron Grotsky
1Department of Emergency Medicine, University of California, Irvine School of Medicine, Orange, California, USA.
Objective:
In this observational study, a modified version of the Visual Function Index (VF-14) and the Snellen Visual Acuity Test were compared in how well they correlated with self-restricted driving habits in older adults. The VF-14 was originally designed to assess vision in cataract patients; however, in this study, a modified version (mVF-14) was evaluated as a tool for predicting self-restricted driving in older drivers.
Methods:
During a 3-month period, 151 drivers over the age of 65 were screened at the local senior center. In addition to the Snellen Visual Acuity Test and mVF-14, each participant was given a questionnaire about their driving habits, previously used in self-restriction studies.
Results:
Out of 151 total participants, 134 were included and 7 nondrivers and 10 subjects who did not complete all questionnaires were excluded. One hundred one participants exhibited normal visual acuity of 20/40 or better (75%), and 110 scored over 90 on the mVF-14 (82%). Spearman's rank sum correlation coefficient was used to analyze the data and showed significant negative correlation of the mVF-14 and Snellen with self-restricted driving. Individuals with normal vision (20/40 or better on the Snellen eye test) had both high and low mVF-14 scores.
Conclusions:
The study shows that poor vision, as indicated by the Snellen scale and low mVF-14 scores, correlates to self-imposed driving limitations. The mVF-14 showed further distinctions of self-restriction between individuals in the same Snellen Visual Acuity category. Therefore, using the mVF-14 in addition to the Snellen Visual Acuity Test can be helpful to further differentiate visual ability within older drivers who appear to have normal vision.
