Perinatal characteristics may influence the outcome of visual acuity

Visual-evoked potential (VEP) acuity has been used to assess the effects of dietary fats on the integrity of the visual pathway of infants. We investigated prognostic determinants of VEP acuity at 16 wk of age. The results of two randomized dietary intervention trials designed to assess the effect of dietary fatty acids on the visual development of term infants were combined. At entry to both trials (approximately day 5 of life), a blood sample to assess polyunsaturated fatty acid (PUFA) status was collected along with sociodemographic and perinatal characteristics. At 16 +/- 0.9 wk of age, infants underwent VEP testing to measure acuity. There was no effect of dietary treatment on these outcomes within or between trials. Multiple linear regression models were constructed to investigate the effect of perinatal and nutritional variables at study entry on VEP acuity of 185 infants. Higher birth weight was associated with an ability to resolve smaller checkerboard patterns [r2 = 0.05; 95% confidence interval (Cl), -0.10, -0.04 log units]. Male gender (r2 = 0.03; 95% Cl, 0.01, 0.07 log units), day 5 plasma 22:5n-6 (r2 = 0.04; 95% Cl, 0.02, 0.20 log units), day 5 red cell membrane 20:3n-9 (r2 = 0.03; 95% Cl, 0.03, 0.13 log units), and the number of smokers in the household (r2 = 0.02; 95% Cl, 0.00, 0.04 log units) were all associated with poorer VEP acuity scores. It is possible that a combination of perinatal factors could accumulate to either mask or enhance effects of diet on VEP acuity, given the relatively modest effects of long-chain PUFA on visual outcome.