Refractive Error

Purpose: Visual impairment (VI) being a state of physiological or pathological disorders of vision poses a burden on human activities globally. The purpose of this study was to determine the prevalence and risk factors of VI among school children in Delta State. Methods: A descriptive cross-sectional study of 201 respondents aged 6 to 19 years were randomly selected from primary and secondary schools in the three senatorial districts of Delta State. Participants were evaluated using a structured questionnaire, distance Snellen chart, ophthalmoscope, and torchlight. Vision status was defined using World Health Organization categories of visual impairment based on presenting visual acuity (PVA). Data were presented in frequency tables, charts and analysed with Chi-Square statistics. All p-values reported were two-tailed and statistical significance was defined as P < 0.05. Results: The mean age of participants was 12.30± 3.14 years, while 118 (58.7%) were females. The overall prevalence of VI (PVA of <6/18 in the better eye) was 58 (28.9%). The prevalence of mild, moderate, and severe VI was 40 (19.9%), 13 (6.5%), and 5 (2.5%) respectively. Refractive error 47 (23.4%) was the leading cause of VI. The prevalence of VI was higher in females, children 13-19 years, and respondents whose parents’ income per month was >100,000. These observed differences were not statistically significant (p>0.05) Conclusion: Untreated refractive error was the leading cause of VI among school children in Delta State. This is an avoidable cause of VI that can be treated with spectacle prescription to ease the burden of visual loss.

The eyes like every other organ of the body, are biochemical elements that respond to both helpful or harmful biochemical stimuli leading to either a healthy or pathological state. Anaemia, antioxidant vitamin deficiencies and visual impairment (VI) are public health problems resulting in poor eye health globally. This study aimed to determine the relationship among anaemia, antioxidant vitamins and VI as well as the effect of antioxidant vitamins and iron supplements on visual acuity and anaemia. A pretest-posttest study of 201 respondents randomly selected from primary and secondary schools in three senatorial districts of Delta State, Nigeria. Sociodemographic data and visual acuity tests were done before and after intervention. Preventive intervention with a single dose of vitamin A, daily Vitamin C, weekly vitamin E, and twice weekly ferrous sulphate supplements was administered for five weeks. Spectacle prescriptions were administered to correct refractive errors (RE). Pretest-posttest haemoglobin and serum vitamins ACE were done using JENWAY 6320D Spectrophotometer. Data were analysed using SPSS version 28.0. Statistical significance was defined as P< 0.05. Findings showed that 83 (41.3%) were males and 118 (58.7%) were females with a mean age of 12.30± 3.14 years. Prevalence of anaemia and VI at baseline was 38.3% and 28.9% respectively, and 0% and 5.5% post-intervention respectively. Prevalence of vitamins A and C at baseline was 12.4% and 12.9% respectively, and post-intervention was 6.0% and 15.9% respectively. Prevalence of vitamin E at baseline and post-intervention was 0.0% respectively. RE was the major cause of VI with a prevalence of 23.4%. The association between visual impairment at baseline and impaired vision with spectacle prescription intervention was statistically significant (P=0.001). The correlation of anaemia, vitamins ACE and VI were not statistically significant (P>0.05). Odd ratios of vitamins ACE and iron supplements were predicted to decrease the risk of having anaemia and VI, though not statistically significant (P>0.05). This study showed that antioxidant vitamins and iron supplementation as well as spectacle prescription were effective in reducing the prevalence of anaemia, antioxidant vitamin deficiencies and visual impairment among primary and secondary school children in Delta State.