Refractive State in Childhood with Normal Visual Acuity.

Cho, Byung Joo; Choi, Ouk

Original Article

Journal of the Korean Ophthalmological Society 1986;27(4):603-609.
Published online April 1, 1986.

Refractive State in Childhood with Normal Visual Acuity.

Byung Joo Cho, Ouk Choi

Department of Ophthalmology, Yonsei University, College of Medicine, Seoul, Korea.

정상시력 유소년층의 굴절상태

최억(Ouk Choi),조병주(Byung Joo Cho)

Abstract

To manifest visual acuity of 20/20 or better, the requirements are good optical imagery, foveal fixation, intact receptor structure and function, and full integrity of the involved neural pathways. Person with hyperopia of 1-10 diopter or astigmatism of 1 diopter may be able to read the line marked 20/20 of Snellen's chart. Non-cycloplegic and cycloplegic subjective manifest refractions were done on 380 normal eyes with visual acuity of 20/20 or more to observe the prevalence, type and degree of the refractive errors. The results were as follows; 1. In non-cycloplegic subjective manifest refraction, 147 eyes(38.7%) had refractive error such as simple hyperopic astigmatism(50.3%), hyperopia(37.4%), simple myopic astigmatism(6.8%) and compound hyperopic astigmatism(5.4%). In cycloplegic subjective manifest refraction, 183 eyes(48.2%) were ametropia such as simple hyperopic astigmatism (49.7%), hyperopia(38.3%), compound hyperopic astigmatism(8.7%) and simple myopic astigmatism(3.2%). 2. As to the type of astigmatisms, "with the rule" astigmatism was 2.5 times more than "against the rule". 3. Average degree of refractive errors were 0.12 diopter in non-cycloplegic refraction and 0.22 diopter in cycloplegic refraction. 4. The degree of hyperopia was less than 1.00 diopter in all cases of noncycloplegic refractions and in most cases(93%) of cycloplegic refractions. 5. Degree of astigmatism were less than 1.00 diopter in the majority(98%).