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KMID : 1011420090140030083
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Journal of Korean Ophthalmic Optics Society
2009 Volume.14 No. 3 p.83 ~ p.88
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Analysis of the Visual Function in Low Vision Patients and Normals in Canada, Using Contrast Sensitivity
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Seo Jae-Myoung
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Abstract
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Purpose: It is said that persons with low vision (LV) require larger object and longer exposure time to make a visual judgment. The spatial summation stands for the increasing of contrast sensitivity (CS), as the target size is enlarged. Likewise, the term temporal summation is used when the CS increases as the exposure duration is extended. The present study investigates whether or not greater target and longer exposure duration is required for LV subjects than for control subjects.
Methods: Twenty subjects with LV and twenty age-matched controls took part in the study. The CS was measured with a 2 alternative forced choice stair case for 0.7 and 3.0 cycle per degree (c/d) static sinusoidal gratings within a circular aperture. The results were analyzed by mixed ANOVA (2?).
Results: As expected, the CS in the LV group were overall depressed. For spatial summation, mixed ANOVA (2 groups?2 spatial frequencies) gave p values of 0.13 for the effect of group, 0.14 for spatial frequency and there was no interaction (p=0.59). Similarly, for temporal summation the results were p=0.19 for group, 0.31 for spatial frequency and p=0.95 for interaction.
Conclusions: Despite the depression of CS in the LV group, a significant difference for spatial and temporal summation between two subject groups was not reached.
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KEYWORD
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Contrast sensitivity, Low vision, Spatial summation, Temporal summation
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