Contrast sensitivity function of sine-wave gratings in children with acute malnutrition
The aim of this study was to determine the contrast sensitivity curves of sine-wave gratings with spatial frequencies of 0.25, 1.0, 2.0 and 8.0 cycles per degree (cpd) of visual angle in 16 female subjects aged 7 to 9 years old, eight well-nourished and eight with acute protein-energy malnutrition (PEM). All participants had normal visual acuity and were free of identifiable ocular illness. Contrast threshold was measured using a temporal two-alternative forced-choice psychophysical method, at a distance of 150 cm of the stimuli, binocularly, with mean luminance of 40.1 cd/m2. We detected a general decline in contrast sensitivity for children with acute malnutrition at all spatial frequencies compared to well-nourished children. The malnourished group needed in average 1.37 times more contrast to detect the stimulus in comparison with the well-nourished one. Differences between the groups were statistically significant at all spatial frequencies (p < .001). These results suggest that acute PEM changes the visual perception for sine-wave gratings.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Pontificia Universidade Católica do Rio de Janeiro
2009
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1983-32882009000100003 |
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