Abstract
Abstract: :
Purpose: To determine the development of the luminance spatial contrast sensitivity function (SCSF) of preterm infants with no visual complaints throughout the first year of life and to compare it with that of term infants. Methods: 73 healthy infants of both genders, 45 preterm and 28 term, were referred by the University Hospital of the University of São Paulo (HU–USP). Infants born before the 36th week of gestation were considered preterm. Fourteen volunteers with >20/20 Snellen visual acuity the adult control group. Luminance CSFs were measured using the NuDiva version of the sweep–VEP system with a high–resolution video monitor. Vertical sine wave gratings of 0.2, 0.8, 2.0, and 4.0 cicles per degree (cpd) were used, with 0.5 added for infants up to 3 mos. Results: There were no significant statistical differences (p>.05) between preterm and term infant spatial contrast sensitivities in any of the age groups of (Mann–Whitney rank sum T–test). The contrast sensitivity peak occurs between .8 and 2.0 cpd at from –1 to 5 months of age. From the sixth to the ninth months the peak is located at 2.0 cpd, with a narrower dispersion. Between 9 and 12 months it is displaced to a higher spatial frequency, at about 4.0 cpd. Adult SCSs peaked at the same spatial frequency. Conclusions: The development of the SCSF of preterm and term infants is very similar during the first year of life. Neither the reduced gestational time nor the longer visual experience has any effect upon this function.
Keywords: contrast sensitivity • electrophysiology: clinical • infant vision