Infant Visual Acuity and Relationships with Diet and Nutrition

Abstract

Visual processing involves the retina, thalamus, and primary visual cortex and cognitive response to visual information involves the integration of various cortical regions. Measures of infant visual acuity have focused on two main aspects of the visual system; retinal development using electroretinogram (ERG) and visual processing at the level of the primary visual cortex. Visual evoked potential (VEP) and behavioral assessments such as the forced-choice preferential looking are two measures involving processing at or beyond the level of the primary visual cortex. VEP measures cortical response directly and has less inherent variability. Forced-choice preferential looking procedures provide insight regarding the integration of visual information beyond the primary visual cortex. The retinal photoreceptors and the gray matter of the cortex have high docosahexaenoic acid (DHA, 22:6 n-3) content. The majority of research investigating functional outcomes in human infants has repeatedly demonstrated better visual function related to the provision of DHA during the prenatal and postnatal periods in comparison to infants who were not supplemented. Multiple independent research groups have documented that pregnant women have DHA intakes well below current recommendations. In turn, DHA deficits during the prenatal period place the developing fetus at risk for interruptions in visual system development. Although breast milk is the best source of DHA for infants during the postnatal period DHA supplementation is necessary for formula-fed infants. The three main sources of DHA and arachidonic acid oil considered used in infant formulas: marine, egg phospholipid, and single-cell oils. Of the three, single-cell oils are the most efficacious for supplementation of formula-fed infants and women of child-bearing age. Increased efforts toward community-based educational programs targeting women of child-bearing age aimed to increase DHA intake are highly important. Interruptions in visual development can delay the achievement of other developmental milestones with important long-term implications.