Neuroimaging in children with congenital disorders of the peripheral visual system

The study investigates the neurological substrate in children with congenit al disorders of the peripheral visual system (CDPVS), i.e. disorders of the anterior visual pathways and the globe. The design is retrospective; brain MRI and/or CT scans were traced and reviewed for 79 of 254 children with C DPVS on our database. The neuroradiological findings were considered in the context of degree of visual impairment (profound [PVI] and severe [SVI]), developmental outcome (setback and non-setback), and mode of imaging (MRI a nd CT). Scans were abnormal in 40 of 79 (51%) children; 23 of 40 (58%) had more than one lesion; and in some children lesions not previously reported were found. The number of abnormalities per child was significantly higher in the PVI than the SVI group (P<0.05); the level of significance varied ac cording to the method of scanning (MRI, P<0.001; CT, ns). Seven children we re known to have had developmental setback; significantly more brain abnorm alities per child were found in the group with setbacks than in the group w ithout (P<0.001). Eighty-six percent (24 of 28) of MRI compared with 38% (2 2 of 58) of CT scans were abnormal. MRI detected more lesions per child tha n CT (P<0.001). Thus, a significant amount of brain pathology occurs in chi ldren with CDPVS. The number of lesions varies directly with degree of visu al impairment and both correlate with developmental outcome. As brain patho logy will be only one of many factors influencing developmental progress in visually impaired children, prospective multifactorial studies of the CDPV S population, which include MRI studies of the neurological substrate, will be required to clarify the latter.