BACKGROUND The eye is a major sensory organ responsible for vision and childhood development. Blindness in childhood can affect psychological and cognitive development, educational attainment and earning potential. Eye examination in children is pivotal to enhance early detection of ocular diseases for prompt treatment and prevention of avoidable blindness. AIM To determine the effectiveness of eye examination by Community health extension workers (CHEWs) during immunization activities in Lokoja Local Government Area (LGA) of Kogi State in order to enhance early detection and treatment of eye diseases in under-five children. MATERIALS AND METHODS An interventional study conducted from 14th December 2019 to 31st March 2020 in ten randomly selected Primary Health Care (PHC) facilities from ten wards in Lokoja LGA, Kogi State. Seventeen CHEWs from the ten selected health facilities were trained on basic eye examination of under-five children using pen torch. They all answered a self administered questionnaire pre- and post- training. All CHEWs attained a minimum interrater agreement of 0.6 and above with the principal investigator after pilot study and were eligible to participate in the fieldwork. Six hundred and fifty-five children (655) <5yrs attending immunization clinics were selected from ten PHC facilities using multistage random sampling with probability proportional to size. CHEWs and the principal investigator independently examined the children’s eyes for deviation, abnormal involuntary movement, protruding eyeballs, redness, discharge and whitish speck/ reflex. These findings and demographic information were recorded on questionnaires. Three months after completion of the study, ten xi v randomly selected CHEWs from the ten PHC facilities were enrolled in a post study review to assess the impact of the training. RESULTS Seventeen (77.3%) of the 22 CHEWs in the ten PHC facilities were trained, while 14 (82.4%) out of the 17 trained CHEWs participated in the study across the ten PHC facilities. Six hundred and fifty-five children were examined. The mean age of the children was 6.3 months + 5.89, age range <1 month -36 months with male: female ratio of 1.03:1. Abnormal involuntary eye movement and whitish speck in both eyes had the highest sensitivity, specificity, positive predictive value and negative predictive values of 100% respectively. Redness, discharge, and eye deviation similarly had high sensitivity, specificity, and negative predictive values while protrusion of the eyes had the least sensitivity and positive predictive value of 0% respectively. The prevalence of eye diseases during the study period was 4.12%, (95% CI 3.67 - 4.57). Ocular diseases seen during the study period were bacterial conjunctivitis 8 (1.22%), allergic conjunctivitis 5 (0.76%), strabismus 3 (0.46%), congenital ptosis 3 (0.46%), neonatal conjunctivitis 3 (0.46%), congenital cataracts 2 (0.31%), nystagmus 2 (0.31%) and traumatic cataract 1 (0.15%). Bacterial conjunctivitis was the most prevalent ocular disease, with a prevalence of 1.22%. Pre- and immediate post-training assessment using paired t-test revealed a statistically significant improvement in the CHEWs’ knowledge to identify and refer eye diseases in under-five children (p<0.001), knowledge of eye diseases requiring urgent referral in children (p= 0.004), and knowledge of specific benefits of eye examination of under-five children (p<0.001). The significant improvement in the perceived knowledge of CHEWs to identify and refer eye diseases in children and specific benefits of eye examination of underfive children at immunization visits was sustained three months after the study with all CHEWs consistently willing to render Primary eye care services during immunization activities in their PHC centres and willing to undertake further training in eye care service delivery.