Table of contents


Evidence reviewed as of before 20-05-2021

Author(s): Ogourtsova, T. (PhD OT) & Osman, G. (MSc OT student)

Visual acuity

We found one method-comparison study (Longmuir et al., 2015) on a telerehabilitation assessment Web-based vision-screening test (WBT) and Electronic Visual Acuity Tester (EVA).

Purpose of assessment
The focus of WBT and EVA is to evaluate visual acuity.
Health discipline
WBT and EVA were administered by an ophthalmologist.
WBT and EVA were administered to children (n=203) with Amblyopia, aged 3.4-12.1 (mean= 7.4 yrs), 96M:107F.
Equipment & platform
  • Equipment used: PC, ruler (or dollar bill—for calibration), eye-patch (or scotch-tape with tissue paper)
  • Platform used: Adobe Flash (software to calibrate size of test optotypes)
Face-to-face comparison
A face-to-face comparison was conducted using the same assessment (WBT and EVA) in person.
  • Moderate sensitivity (78.7%) for the WBT
  • High specificity (89.4%) for the WBT
  • Strong correlation between EVA and WBT (0.89)
  • Low error rate (26.1%)
Training required
  • WBT: certification needed - to be administered by certified persons with 3-5 years of training as Vision Screener.
  • EVA: Initial Certification of the EVA. Each PC tester unit must be certified for use. Certification is obtained by performing an initial calibration on the EVA. 3.
Longmuir, S.Q., et al., Validity of a layperson-administered Web-based vision screening test. Journal of Aapos: American Association for Pediatric Ophthalmology & Strabismus, 2015. 19(1): p. 29-32.