Study of visual acuity and comparison of Snellen chart and retinoscopy in diagnosis of refractive errors

ABSTRACT

Refractive errors play important role in the etiology and treatment of strabismus and amblyopia. As screening is one of the common techniques in diagnosing visual disorders, children are, therefore, to be examined for the health of their vision at least once a year. This study is intended to compare the accuracy of Snellen chart and retinoscopy in diagnosis of refractive errors. The target population included guidance-school children in grade one from Sabzevar [2008 female and 2085 male subjects]. Relevant data were collected through interview and clinical examination. Visual acuity of the subjects was examined from a distance of 6m by Snellen chart and those with VA< 10/10 were examined with retinoscopy by an ophthalmologist. The mean visual acuity of both eyes in girls and boys obtained by the Snellen chart turned out to be 0.95 +/- 0.12 and 0.97 +/- 0.09 respectively. Also, 294 subjects appeared to be suffering from refractive errors. In 65% of the cases a significant difference was found between Snellen chart and retinoscopy in diagnosis of refractive errors [p<0.05]. Further research is suggested to reveal the possibility of differences of VA between girls and boys