Prevalence, pattern of refractive error and visual impairment among secondary school students in Kawempe Division, Kampala District

Abstract

Introduction: Recent estimates by the World Health Organization (WHO) suggest that 2.2 billion people are visually impaired, uncorrected refractive error accounts for 123.7 million, cataract 65.2 million, age-related macular degeneration 10.4 million, glaucoma 6.9 million,corneal opacities 4.2 million, diabetic retinopathy 3 million, trachoma 2 million, and other causes 37.1 million. In Uganda, eye diseases are among the top ten conditions for Out Patient Department (OPD) attendance with an estimated prevalence of blindness at 0.4%. Most of the Visually impaired or blind children miss out on education and become long term dependants on their families. There is limited study and literature on the prevalence of REs and VIs in secondary school students in Uganda. If the students’ vision is not assessed at this stage, many refractive errors could go undetected and can affect their vision later in life. The aim of this study was to determine the prevalence, pattern of refractive error and visual impairment among secondary school students, in Kawempe division, Kampala district. Methods: A cross sectional study design was conducted among 2 governments and 2 private secondary schools in Kawempe Division, Kampala district in which 394 students selected by systematic sampling method were recruited. Materials such as visual Acuity charts, HRR colour vision pseudo isochromatic plates, occluders, trial cases, trial frame, retinoscope and RESC assessment tool were used. Ethical approval was obtained from IRB School of health sciences Makerere University with maximum privacy and confidentiality of participants maintained all the time. The data collected was analyzed using SPSS v18 and presented in form of frequency tables, pie-charts and bar-graphs. Results: A total of 394 students participated in the study (response rate of 100%). The mean age was 16 (±2.07), youngest 12 years and the oldest 20 years. 169 (42.9%) were males while 225 (57.1%) were females. Visual acuity was normal in 92.4% and 85.3% for both right and left eyes respectively. There was no participant found with any tropia at 0.5 or 4 metre fixation. Majority of the respondents 393 (99.7%) had a full visual field with only 1 (0.3%) participant found with restricted vision in superior nasal area. Also, 392 (99.5%) children had a normal colour vision as only 1 (0.3%) had mild blue-yellow and another 1 (0.3%) mild red-green defects. The prevalence of visual impairment was 15.5% of which 15.2% had a refractive error. Myopia 37 (9.4%), hyperopic 3 (0.8%) and astigmatism 20 (5.1%) were the most common refractive errors in students.

Conclusions: The prevalence of Refractive Errors and Visual Impairment among secondary school students was 15.2% and 15.5% respectively. Out of the 60 participants who had refractive errors, only 7 (11.7%) had corrective lenses and 53 (88.3%) did not have corrective lenses. Periodical screening of secondary school students and preschool children for refractive errors is highly recommended.