Comparison of the visual function index to the Snellen Visual Acuity Test in predicting older adult self-restricted driving.
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.
Lotfipour
Shahram
S
Department of Emergency Medicine, University of California, Irvine School of Medicine, Orange, California, USA.
Patel
Bhakti Harishchandra
BH
Grotsky
Thomas Aaron
TA
Anderson
Craig L
CL
Carr
Erin M
EM
Ahmed
Suleman Syed
SS
Chakravarthy
Bharath
B
Fox
John Christian
JC
Vaca
Federico E
FE
D000368:Aged; D000369:Aged, 80 and over; D001334:Automobile Driving / Q000523:psychology*; D006801:Humans; D012647:Self-Assessment; D011795:Surveys and Questionnaires; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity