Abstract
Purpose :
To measure the repeatability of contrast sensitivity measured using the Ohio Contrast Cards (OCC), before and after cycloplegia, in a general pediatric optometric population. The OCC (Precision-Vision, Woodstock IL) present 0.15 cy/deg horizontal square-wave gratings of variable contrast (stepsize=0.15 Log10 units) on cards similar to the Teller Acuity Cards.
Methods :
We used the OCC to measure monocular contrast sensitivity (CS) on 41 non-amblyopic children (ages 4-11, mean=7.8, SD=2.1). Each child’s CS was measured twice, by different examiners, before their routine, dilated, cycloplegic eye exam. After the exam, when the eyes were still cyclopleged (Tropicamide, Cyclopentolate, or both), CS was measured again. Children who wore glasses were tested with their glasses on before and after the exam, and again after the exam, without their glasses. Refractive errors were obtained by wet retinoscopy. The study was powered to reveal a test-retest difference of one card at corrected p<0.05 with power=0.90. We compared the results of the first test, which was pre-cycloplegia and pre-exam, to the results of the post-cycloplegia, post-exam test. For children who wore glasses, we compared the pre- and post- tests with glasses on; otherwise we compared tests with glasses off.
Results :
The pre-exam and post-exam results were similar (mean LogCS=2.07, SD=0.14; mean LogCS difference=0.01, SD=0.12). The 95% limits of agreement (±1.96 x SD[difference]) were ±0.24 Log units, and weighted Cohen’s K=0.59, 95% CI=0.38–0.80. Under cycloplegia, the uncorrected blur for horizontal gratings at the test distance was +0.08 D to +5.27 D (mean=1.71 D, SD=1.08 D), and uncorrected CS under cycloplegia was not associated with blur (r= -0.01, p=0.94). Mean LogCS, measured across the two pre-exam tests was 2.07 (SD=0.15), and those were also closely similar (mean difference=0.02 Log units, SD=0.12) and highly correlated (r=0.73, p<0.0001), and the intra-examiner repeatability was high (weighted K=0.70, 95% CI=0.53–0.87).
Conclusions :
The Ohio Contrast Cards show good repeatability in this population when pre-exam pre- cycloplegia tests are compared to post-exam post-cycloplegia tests, indicating that the cards can be used without regard to cycloplegia. There is no significant effect of refractive error on the measurements, showing that the Ohio Contrast Cards is an effective near test used under cycloplegia on a range of refractive errors.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.