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A.M. Betts, K.S. Bower, D.K. Bigelow, J.C. Rabin, J.M. Burka, R.C. VanRoekel; Low–Contrast Visual Acuity and Small Letter Contrast Sensitivity in Adult Patients With Refractive Error . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4374.
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© ARVO (1962-2015); The Authors (2016-present)
To establish normative values for a low–contrastvisual acuity (CA) test and a small letter contrast sensitivitytest (SLCT) in a sample of patients with refractive error. Pre–op records of 438 patients who underwent refractivesurgery at an Army laser center were reviewed. 5% CA, SLCT score,manifest and cycloplegic refraction, and age were recorded fromeach patient’s record. The distribution of scores forcontrast testing was analyzed and examined for correlationswith age and refractive error. The mean logarithmic5% CA was 0.34 for both right and left eyes (20/44 Snellen equivalent).The mean logarithmic SLCT score was 0.38 (contrast thresholdof 42%) for the right eyes and 0.40 (threshold 40%) for theleft eyes. The mean SLCT score was lower than previously reported.Higher levels of myopia were associated with poorer performanceon both tests. Neither test showed significant correlation withage in this sample. This retrospective review providesnormative values for two methods of contrast testing in a militaryrefractive surgery clinic. The inverse correlation between myopicrefractive error and performance on contrast testing may beattributed to optical effects of spectacle correction and/orretinal factors in myopic eyes. The reduction in SLCT comparedto previously established values is likely attributed to thenon–standard luminance conditions under which the SLCTwas administered in this clinical setting.
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