A scoping review on clinical and genetic diagnostic approaches for cerebral visual impairment

In recent years, the prevalence of cerebral/cortical visual impairment (CVI) in pediatric population has risen in developed countries; however, the condition's heterogeneity complicates its assessment and the creation of standardized diagnostic and treatment protocols. We review current clinical and genetic approaches to the diagnosis of CVI. A PubMed search conducted in October, 2024, identified original articles on the genetic and clinical diagnosis of children or young adults with CVI or at risk. Articles differentiating CVI from other diagnoses or typically developing children, as well as those examining screening tools, were also included. Of 565 references, 10 focused on the genetic features of CVI and 56 on clinical characteristics using different protocols or tests. Up to 40 % of CVI patients showed chromosomal abnormalities, and 26.9 % had genetic pathogenic variants linked to seizures, global developmental delay, intellectual disabilities, or birth complications. Ten of 17 questionnaires or screening tools are validated. Diagnostic protocols for identifying or diagnosing CVI (n = 12) included medical history, parent reports, visual field testing, optic nerve and oculomotor examinations, and visual perceptual assessments. Individuals with CVI showed poor visual performance on eye tracking (n = 9). Different visual evoked potential tests can help detect CVI (n = 9), and some studies highlight magnetic resonance imaging abnormalities in the dorsal and ventral stream and the thalamus. Several tests and screening tools are used to diagnose CVI, but their limited validation and variability make it challenging to establish precise protocols. Genetic testing can provide essential diagnostic information given the numerous genes involved, particularly after the main possible causes have been excluded.