Cerebral visual impairment in preterm infants with periventricular leukomalacia

Neonatal brain lesions are the main cause of cerebral visual impairment in infancy, i.e., of a visual deficit caused by damage to posterior visual pathways. Visual outcome of preterm infants with periventricular leukomalacia (PVL) was investigated in 14 subjects affected by severe cystic PVL, another 34 with moderate PVL (prolonged periventricular echodensities), and 18 control preterm infants. All cases with significant ocular abnormalities (such as retinopathy of prematurity state III or upwards, optic nerve atrophy, or major refraction problems) were excluded. Visual acuity, visual field, eye alignment, fixation and following, optokinetic nystagmus, and visual threat were tested at 1 year of corrected age. A high incidence of cerebral visual impairment, consisting mainly of low visual acuity, severe oculomotor disorders, and reduced visual field, was found in infants with severe PVL. Visual defects were less frequent and less severe in the moderate PVL group, and very rare in the control group. The results of neuroimaging, and especially of magnetic resonance imaging, correlated with the visual outcome and indicate lesions at the level of optic radiations as the main anatomic substrate of the visual impairment. All infants with PVL need a visual follow-up, from the first months of life, the results of which are important both for visual and motor rehabilitation of these cases and for their daily care.