Abstract
Purpose: :
To determine if the prevalence of the ocular motor signs of the infantile strabismus complex increases as a function of the severity and extent of cerebral visual pathway white matter injury (CVPWMI). CVP was defined as the posterior optic radiations and the splenium of the corpus callosum.
Methods: :
MRIs obtained ≥ age 2 yrs were scored using a standardized system (CVPWMI graded 1-3) in 67 children (mean GA 31 wks; mean BW 1885 g) who had WMI detectable as periventricular leukomalacia with or without reduced volume of the splenium. Masked ophthalmologic and orthoptic examinations were performed on the CVPWMI group and a GA-matched control group who had normal MRIs.
Results: :
Infantile strabismus (primary eso: exo 3.5:1) was documented in 60% of grade 1, 77% of grade 2, and 86% of grade 3 CVPWMI children, respectively. Other ocular motor signs of the complex increased with CVPWMI grades 1-3: latent/manifest latent nystagmus (20%; 47%; 46%), DVD (13%; 26%; 27%), and nasotemporal pursuit/OKN asymmetry (13%; 37%, 37%). The prevalence of each of these signs in the control group was ≤ 8% (ANOVA and chi-square < 0.05). CVPWMI grade related also to the prevalence of retrograde (axial and sectoral) optic neuropathy (6%, 27%, 36%).
Conclusions: :
Children who suffer CVPWMI develop the ocular motor signs of the infantile strabismus complex at rates substantially exceeding those of non-CVPWMI children. The prevalence of the signs increases with CVPWMI severity. These findings reinforce the conclusion that the infantile strabismus complex is caused by prenatal/perinatal damage to cerebral visuomotor pathways.
Keywords: strabismus • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual development: infancy and childhood