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K.S. Bower, J.C. Rabin, R.D. Stuzman, J.M. Burka, R.C. VanRoekel, A.M. Betts; A Prospective Evaluation Of A New Test Of Contrast Sensitivity And Disability Glare For Use In Refractive Surgery . Invest. Ophthalmol. Vis. Sci. 2006;47(13):520.
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© ARVO (1962-2015); The Authors (2016-present)
Contrast sensitivity (CS) can reveal decrements in vision despite normal high contrast visual acuity (VA). We used a commercially available letter CS test to assess visual performance in refractive surgery.
In this prospective, non–randomized, clinical investigation, 50 subjects underwent either photorefractive keratectomy (PRK) or laser–assisted in situ keratomileusis (LASIK). Best spectacle–corrected high and low contrast VA and small letter CS (20/50 letter size, PrecisionVision®) was assessed at normal and low luminance with and without glare.
At 1–week post–operative, CS was decreased in PRK (mean decrease = 0.35 log CS, p<0.001) and in LASIK (0.32 log CS, p<0.001), with the decrease greater in PRK at low luminance and with glare. At 1–month post–op CS was improved in PRK and LASIK, but remained below baseline (p<0.05). From 1 to 6 months CS continued to improve in PRK eventually reaching baseline, but in LASIK CS stabilized below baseline performance (p<0.05; see figure). A similar effect prevailed for low contrast VA. The results are consistent with a greater impact of higher order aberrations in LASIK vs. PRK, the impact of which becomes evident with low contrast testing.
This CS test provides enhanced sensitivity for detecting subtle decrements in vision undisclosed by high contrast VA. It holds promise for quantifying improved vision anticipated after correction of higher order aberrations.
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