Visual impairment and perceptual visual disorders in children with cerebral palsy in Nigeria

Cerebral palsy (CP) is the most common cause of childhood physical disability globally. This study describes the spectrum of ocular morbidity and visual impairment in a community-based (recruited by key informants) sample of children with CP in Cross River State, Nigeria.

Methods: A paediatric neurologist clinically confirmed CP and assessed systemic comorbidity. Ophthalmological assessment included developmental age appropriate acuity tests, objective refraction and objective and subjective tests of perceptual visual dysfunction (PVD).

Results: 388 children aged 4-15 years with CP were identified. Visual problems were reported by carers in only 55 (14%) cases. Binocular visual acuity impairment was seen in 20/201 by Lea symbols test (10%) and 213/388 (55%) by the mirror test. Abnormal visual fields were seen in 58/388 (14.9%); strabismus in 183 (47%) abnormal contrast sensitivity in 178 (46%) and abnormal saccades in 84 (22%), spherical refractive errors in 223 (58%), significant astigmatism in 36 (12%), accommodative dysfunction in 41 (10.6%), optic atrophy in 198 (51%). Perceptual visual disorders were present in 22 (6%) subjectively and 177 (46%) objectively. The estimated frequency of cerebral visual impairment (CVI) in children ranged from 61 (16%) to 191 (49%) if children with optic atrophy were included.

Conclusion: Children with CP have a wide spectrum of ocular morbidity and visual impairment, underestimated by carers. Children with CP require visual acuity assessments with a range of tests which account for associated comorbidities and oculomotor dysfunction. Functional vision assessments for PVD is important. CVI is common.