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Seong Taek Jeon, Daphne Maurer, Terri Lewis; The Effect of Early Visual Deprivation on Sensitivity to Orientation in First- and Second-order Patterns. Journal of Vision 2011;11(11):407. doi: 10.1167/11.11.407.
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We examined the effect of early visual deprivation on the development of sensitivity to orientation in 11 patients treated for bilateral congenital cataract (mean duration of deprivation = 107 days; range: 11–196) and 11 patients treated for unilateral congenital cataract (mean duration of deprivation = 109 days; range: 7–245). Patients were 6–30 years old at the time of the test. Each subject judged the orientation of supra-threshold first-order (luminance-modulated) and second-order (contrast modulated) 1 c/deg sinusoidal gratings that were matched in space-average luminance and were created using static binary random noise. First-order stripes without noise were included as a control. The task on each trial was to judge whether the stripes were tilted to the left or right of vertical. Over trials, the orientation of the stripes was varied according to a PEST staircase (Harvey, 1997) that terminated after it reached a threshold at 82% correct with 95% confidence. Patients' thresholds were converted to z-scores by comparison to the appropriate age-matched control group. For first-order stripes, both groups of patients performed normally with and without added noise (ps > 0.10). For second-order stripes, all 11 patients treated for bilateral cataract had negative z-scores and the mean was significantly below zero (t(10) = −3.564, p < 0.01), but 3 of the 11 patients had z-scores less than −3. The deficits for second-order stripes were not correlated with acuity nor age at test in either patient group (ps > 0.20). The results suggest that second-order processing is more vulnerable than first-order processing to the effects of early visual deprivation, perhaps because it involves additional processing (Chubb & Sperling, 1988); input through a non-deprived eye may decrease the vulnerability.
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