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R. G. Bosworth, S. L. Robbins, D. Chao, K. R. Dobkins; Luminance and Chromatic (Red-Green) Contrast Sensitivity for Temporally Modulated Gratings in Preterm Infants and Infants with Mild/Moderate Retinopathy of Prematurity. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2737. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To determine whether contrast sensitivities (CS) designed to tap magnocellular (Magno) and parvocellular (Parvo) pathways are impaired in infants with spontaneously regressed ROP; and, to determine whether healthy preterm infants match fullterm infants in postnatal age (PNA), suggesting CS development is influenced by visual experience, or in postconceptional age (PCA), suggesting development follows biological maturation.
Using forced-choice preferential looking (FPL) techniques, contrast thresholds were obtained for luminance (Magno, black/yellow) and chromatic (Parvo, red/green isoluminant) sinusoidal gratings (0.27 cpd; 4.2 Hz; mean luminance = 20 cd/m2). Five cone contrasts (Magno: 2-46%, Parvo: 2-24% cone contrast) were presented, randomized across trials. Weibull functions were fit to accuracy data to obtain a threshold for each infant.
Sixty-nine healthy preterm infants, 131 fullterm infants, and 17 ROP infants were tested between 2-12 mos PNA. Treating birthweight, postnatal age, and prematurity as covariates, ROP infants were significantly worse than age-matched preterm controls for luminance CS (p = 0.01) but not for chromatic CS (p = 0.07). In preterm infants, luminance CS was better matched to fullterms in PCA while chromatic CS matched PNA between 2-6 months of age.
In the first year of life, luminance sensitivity, mediated by the Magno pathway, appears to be governed mainly by biological maturation. By contrast, red-green chromatic sensitivity, mediated by the Parvo pathway, is clearly influenced by early postnatal visual experience. ROP appears to impair Magno pathway maturation. Further examination of more ROP infants, refractive error development, and longitudinal testing to see if the Magno deficit persists after the first year of life will be conducted.
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