Visual acuity screening, photoscreening and dispensing of glasses with ready to Clip^™ technology

Abstract

Background:

The visual screening performed in schools is sometimes the only opportunity to detect uncorrected refraction errors (URE) causing low visual impairments, prejudice in the acquisition of knowledge, dropout and school repetition, poor motor skills, difficulty in social interaction and low self-esteem in schoolchildren.

Objectives:

To compare the detection of URE in elementary school children by visual screening (measurement of the AV with the Snellen table) and photoscreening; to evaluate the accuracy of the SpotTM Vision Screener (Welch Allyn) as an autorefractor by comparing its refraction measurements with those of the autorefractor Topcon KR 800 (Japan) and to verify the proportion of glasses with ready to ClipTM technology dispensed at the time of the students’ evaluation.

Methods:

Two hundred ninety-seven students were submitted to visual screening (cutoff point: AV monocular ≤ 0.7 and/or difference two Snellen lines between the eyes), photoscreening (cutoff point: hypermetropia ≥ 3, 00D, myopia ≥ 0, 75D and astigmatism > 1D) and the measurement of the refraction error under cycloplegia with the photoscreener and autorefractor. Only the refraction data of the right eye were analyzed. The findings were converted into vectors of magnitude for analysis.

Results:

The sensitivity and specificity values of the visual screening method were 67.2% and 63.5% and photo screening were 76.1% and 79.1%. The mean difference between refraction by SVS and autorefractor was of + 0.154 SD combined with -0.170 DC in the 6-degree axis for the right eye of each patient.

Conclusions:

In the population evaluated the method of refractive screening by photoscreener was more effective than the visual screening. The comparison of the results of refraction under cycloplegia with the autorefractor validated the use of photoscreener as an accurate refraction method for the measurement of refractive errors in schoolchildren. The majority of the students received their glasses with ready to Clip™ technology at the time of prescription.

Keywords:
Visual acuity/diagnosis; Ophthalmologic diagnostic techniques; Ocular refraction; Vision disorders; School health