Prevalence and Pattern of Cerebral Visual Impairment Amongst Children Attending Kenyatta National Hospital Eye Clinic

Abstract

Background: In the absence of injury to the anterior afferent visual pathways or the ocular structures, cerebral visual impairment (CVI) is characterized by vision loss caused by damage to the retro-geniculate pathway or by vision loss that is more than anticipated given the severity of ocular pathology. Ocular pathologies such as refractive errors may coexist but insufficient to cause severe vision impairment. Common causes of CVI include birth asphyxia, meningitis and hydrocephalus. Studies on CVI in Sub Sahara Africa are limited as it is listed under other causes of visual impairment or blindness and not as an individual entity. Several patients had been diagnosed with cerebral visual impairment at Kenyatta National Hospital eye clinic however, no audit of the condition had been done. Objective: To describe the prevalence and pattern of cerebral visual impairment in children attending Kenyatta National Hospital eye clinic. Design: It was a retrospective, hospital-based study. Study location: The study was done at Kenyatta National hospital eye clinic. Methods: The study included all children with CVI seen at Kenyatta National hospital eye clinic from 1st January 2019 to 28th February 2021. A standardized questionnaire was used to obtain patient data. The variables of interest included known causes of cerebral visual impairment, age at diagnosis, age at presentation, associated non-ocular co-morbidities, ocular examination findings and refractive status. Prevalence of CVI was calculated from this study population. Data was analyzed using SPSS Version 24 software. Descriptive statistical analysis and inferential analysis was used. Results were presented in text, tables, graphs and charts. Results: A total of 674 children were reviewed and 53 children met the study inclusion criteria. The prevalence of CVI was 7.9%.The male to female ratio was 1.4:1with the mean age at presentation of 25.9 months. The main presenting complaint was poor vision (100%). The main known cause of CVI was meningitis/encephalitis (41.4%) followed by birth asphyxia (31%). Half of the children were not fixing or following light. The main ocular examination finding was optic atrophy (39.6%). The main refractive error was simple hyperopia (41.7%). The commonest 12 non-ocular co-morbidity was delayed milestones/motor impairment (61.5%). Some children had more than one non-ocular co-morbidity. Conclusion: All children presented with poor vision. The commonest known cause was meningitis/encephalitis. More than half of the patients had severe visual impairment. The main ocular finding was optic atrophy. Simple hyperopia was the commonest refractive error. The commonest non-ocular co-morbidity was developmental delay/motor impairment