Background: The Vision Screener is a new, commercial version of the Power Refractor, an off-axis, hand-held video refractor to screen for amblyogenic refractive errors. The aim of our study was to determine the reproducibility of the measurements, compare them to cycloplegic refraction, and evaluate the sensitivity and specificity for the detection of amblyogenic refractive errors.
Patients and methods: Included in the study were 161 preschool children, age 0.5-7.2 years without manifest strabismus > 10 degrees , who attended the outpatient clinic. After three measurements with the Vision Screener (version 4.3.15) and one measurement with +3 dpt glasses, the child underwent cycloplegic refraction.
Results: The reproducibility of the three non-cycloplegic measurements was +/- 0.5 dpt in 85% and +/- 1 dpt in more than 95% of the children. Accommodation reduced the manifest hyperopia that could be measured with the Vision Screener by up to 3 dpt in some children. Compliance with the +3 dpt glasses increased from 20% in those under one year of age to > 75 % in those over three. The glasses did increase the sensitivity from 70% to 80% but decreased the specificity from 80% to 65%.
Conclusion: The Vision Screener is easy to handle and gives reproducible results. The sensitivity and specificity are between 70 and 80%. The +3 dpt glasses are only helpful in a few patients. The latest software version with a new algorithm is now under evaluation.