**Background:** Visual impairment (VI) and blindness in children are major public health issues, especially in low- and middle-income countries like Nigeria, where over 80% of vision impairment occurs. Children with VI face lifelong developmental and socioeconomic challenges. Despite Nigeria having a large child population (over 110 million under 18 years), nationally representative data on childhood blindness and VI are lacking. This systematic review aimed to aggregate existing evidence from the last 20 years to determine the prevalence and causes of blindness and VI among Nigerian children, thereby informing health policy.
**Methods:** This was a systematic review without meta-analysis (SwiM), reported following PRISMA guidelines. The review included primary cross-sectional studies published in English between 2003 and 2022 that reported the prevalence and/or causes of VI or blindness in Nigerian children under 20 years. Searches were conducted in PubMed, AJOL, BASE, and ProQuest from June 6 to July 15, 2023. Study quality was assessed using the AXIS tool. Visual impairment was defined using presenting visual acuity in the better eye according to WHO classification: mild (<6/12–6/18), moderate (≤6/18–6/60), severe (≤6/60–3/60), and blindness (≤3/60). Due to heterogeneity, meta-analysis was not possible; descriptive statistics (mean and range) were used to estimate prevalence from nine community-based studies, which better represent the general population.
**Key Results:** Seventeen studies, involving 16,924 children from 13 states across five of Nigeria's six geo-political zones (GPZ), were included. The overall mean (range) prevalence of blindness was 0.3% (0.2–0.4%). For mild, moderate, and severe VI, the mean prevalences were 3.9% (0.2–15.9%), 2.9% (0.1–10%), and 0.2% (0.1–0.5%), respectively. The highest prevalence of VI was in the North-Central GPZ (15.9% mild, 8% moderate), while the lowest was in the South-South GPZ (0.75%). The leading causes of mild to severe VI were refractive errors (ametropia), cataracts, corneal opacities, glaucoma, and amblyopia. For blindness, the most common causes were cataracts (40% in one study), optic atrophy, corneal scars, and trauma. Notably, cataract was the most frequent cause of blindness across studies, while ametropia was the predominant cause of VI.
**Clinical Implications:** This review provides the first nationally representative estimates of childhood blindness and VI in Nigeria. The findings underscore that the major causes—cataract and ametropia—are largely preventable or treatable. Cataract blindness can be addressed through high-quality pediatric cataract surgery, which requires specialized training and improved access to eye care services. Refractive errors can be corrected with spectacles, yet global access to such correction is only about 36%. The review also highlights the persistent burden of corneal opacities from causes other than vitamin A deficiency, as well as the harmful effects of traditional eye medications. Public health strategies should include continuous health education, legislation against harmful practices, and strengthening the eye care workforce, particularly in underserved GPZs like the North-West. The data can guide policymakers in designing targeted interventions to reduce avoidable blindness and improve visual outcomes for Nigerian children.