Factors Limiting Visual Outcome
Visual acuity may be compromised in premature infants as a consequence of foveal dragging, foveal detachment, and disorganization of retinal elements, as well as the destructive impact of blood in the subfoveal space. Blood in the subretinal space, toxic to the retina and retinal pigment epithelium and photoreceptors, may cause irreversible damage that limits visual improvement. In addition, central nervous system changes as a consequence of anisometropic amblyopia or problems such as periventricular leukomalacia that limit access of visual information to the visual cortex may also limit functional outcome.
Prematurity may also impact development of normal foveolar cellular and vascular architecture despite the absence of foveal detachment or tractional distortion. Optical coherence tomography (OCT) studies demonstrate the foveal depression may be ovoid and shallow in infants born prematurely. This abnormality in the depth of the foveal depression may occur as a consequence of reduced migration of cells from the foveal area as a consequence of VEGF imbalance on vascular remodeling. Limited foveolar differentiation might be expected to limit visual potential, and could be yet another explanation why visual acuity in some children with ROP is reduced.
Recchia FM, Recchia CC. Foveal dysplasia evident by optical coherence tomography in patients with a history of retinopathy of prematurity. Retina. 2007 Nov-Dec;27(9):1221-6.