Time required for screening for visual impairment in primary care: a randomized comparison of 3 common visual tests

To determine the time required for adults older than 50 years to complete 1 of 3 vision impairment assessment tools in a family medicine residency office.

Patients older than 50 years with no known cognitive or physical deficits that impaired ability to follow directions or complete screening tasks were invited to participate in this trial. Participants were randomized to complete 1 of 3 screening modalities, namely, the Functional Vision Screening Questionnaire (questionnaire), mixed contrast sensitivity reading card (card), or Snellen eye chart (Snellen). The time required to complete the vision assessment was obtained and recorded.

Sixty-nine patients, with a mean age of 63 years (SD, 10), participated in the study. The card required 94 less seconds to administer than did the questionnaire (95% confidence interval, 61.24 to 127.11 seconds). Similarly, the card required 67 less seconds to administer than did the Snellen (95% confidence interval, 34.20 to 100.06 seconds). No significant difference existed between time to administer the questionnaire and the Snellen (mean difference, 27 seconds; 95% confidence interval, -5.89 to 59.97 seconds).

Primary care-based vision screening may detect patients with impairment who would otherwise not have vision assessment. However, a time-intensive screen will not likely be successfully implemented in a primary care office. The card required statistically significantly less time to administer than did the questionnaire or Snellen. With all modalities requiring at least 1 minute, perhaps none are suitable for use for universal, primary care-based vision screening programs. Further work is needed to characterize the reliability and ease of use of each tool.