Purpose:
In approximately 40 states, drivers with low vision who cannot meet vision standards with conventional optical correction are permitted to use bioptic telescopic spectacles (BTS) to obtain licensure. BTS are spectacles with telescopes mounted superiorly, designed to allow low vision drivers to identify signs and other objects at a greater distance. The purpose of this investigation was to examine visual and demographic factors, and their relationship to training hours and road test results.
Methods:
A retrospective review of records of patients who completed an initial bioptic examination at the College of Optometry at the Ohio State University was initiated. Patients were identified by CPT code in the College’s patient record system. Data were collected on vision including visual acuity (logMAR charts), contrast sensitivity (Pelli Robson or Mars charts), visual field (arc perimeter or Goldmann), and glare sensitivity and recovery (BAT). Demography, ocular diagnosis, licensure history, and driver training and testing for licensure with BTS were also recorded. Relationships between hours of training before the driving instructor judged the patient ready for a road test and vision data and road testing results were investigated evaluated with linear and logistic regression and ANOVA.
Results:
Fifty patients (28 males) were identified as having completed an initial vision examination, with 34 reporting some prior form of licensure. Age at initial exam ranged from 17 to 78 years (mean = 39±14 years). Of the 50 patients, 34 (68%) were documented as having subsequently passed a road test and received a license to drive with BTS. Of all patients with documented training and road test reports (n=26), 23% failed a road test at least once. Higher age was related to having failed a road test (p=.036). The mean (±SD) number of hours of training prior to road testing was 17±16. Higher total hours of training was related to decreased horizontal visual field (p = 0.018), lack of previous licensure (p = 0.027) and test type (daylight vs. night) (p = 0.027). Common errors on road testing included "improper steering - erratic, weaving" (32% of patients), "improper braking" (32%), "drives too fast/slow for conditions" (21%), and "turns too wide/short" (16%).
Conclusions:
Approximately 2/3 of those who presented for an initial exam eventually received licensure. Several patient factors were related to the amount of training patients received before road testing.