Related Experiment Video
Updated: Apr 26, 2026

Subjective Refraction Test Using a Smartphone for Vision Screening
Published on: October 18, 2024
Uncorrected refractive error and associated factors among primary school children in Debre Markos District, Northwest
Sintayehu Aweke Sewunet, Kassahun Ketema Aredo1, Molla Gedefew
1Department of Public Health, Debre Markos University, College of Medicine and Health Sciences, PO Box: 269, Debre Markos, Ethiopia. kasyon33@Gmail.com.
Background:
Uncorrected Refractive Error is one of the leading cause amblyopia that exposes children to poor school performance. It refrain them from productive working lives resulting in severe economic and social loses in their latter adulthood lives. The objective of the study was to assess the prevalence of uncorrected refractive error and its associated factors among school children in Debre Markos District.
Method:
A cross section study design was employed. Four hundred thirty two students were randomly selected using a multistage stratified sampling technique. The data were collected by trained ophthalmic nurses through interview, structured questionnaires and physical examinations. Snellens visual acuity measurement chart was used to identify the visual acuity of students. Students with visual acuity less than 6/12 had undergone further examination using auto refractor and cross-checked using spherical and cylindrical lenses. The data were entered into epi data statistical software version 3.1 and analyzed by SPSS version 20. The statistical significance was set at α ≤ 0.05. Descriptive, bivariate and multivariate analyses were done using odds ratios with 95% confidence interval.
Result:
Out of 432 students selected for the study, 420 (97.2%) were in the age group 7-15 years. The mean age was 12 ± 2.1SD. Overall prevalence of refractive error was 43 (10.2%). Myopia was found among the most dominant 5.47% followed by astigmatism 1.9% and hyperopia 1.4% in both sexes. Female sex (AOR: 3.96, 95% CI: 1.55-10.09), higher grade level (AOR: 4.82, 95% CI: 1.98-11.47) and using computers regularly (AOR: 4.53, 95% CI: 1.58-12.96) were significantly associated with refractive error.
Conclusion:
The burden of uncorrected refractive errors is high among primary schools children. Myopia was common in both sexes. The potential risk factors were sex, regular use of computers and higher grade level of students. Hence, school health programs should work on health information dissemination and eye health care services provision.
Related Concept Videos
Focusing of Light in the Eye
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
Diabetic Retinopathy
Common Leveling Mistakes and Errors
Types of Errors: Detection and Minimization
Absolute error in a measurement is the numerical difference from the true or central value. Relative error is the ratio between absolute error and the true or central value, expressed as a percentage.
Errors can be classified by source, magnitude, and sign. There are three types of errors: systematic, random, and gross.
Systematic or...

