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P.C. Mitchell, R.J. Mitchell, E.R. Crouch, Jr., E. Weis; Effect of Laser Epithelial Keratomileusis (LASEK) on Mesopic and Scotopic Contrast Sensitivity . Invest. Ophthalmol. Vis. Sci. 2006;47(13):518.
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To evaluate the effect of laser epithelial keratomileusis on mesopic and scotopic contrast sensitivity.
194 eyes of 108 patients were enrolled in a prospective trial and underwent excimer laser corneal ablation between February 2004 and October 2004. All eyes received LASEK with a prolate shaped ablation profile using the Meditec MEL–80 excimer laser. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive error, and best corrected contrast sensitivity were measured preoperatively. All parameters were remeasured one year postoperatively for comparison. Contrast sensitivity was measured using Sloan translucent contrast charts (Precision Vision, Illinois, USA) and recorded using logmar acuity scale.
The Wilcoxon rank–sum analysis was used to compare the preoperative and postoperative contrast sensitivity measurements. In both mesopic and scotopic conditions, contrast sensitivity improved significantly one year following surgery. Mesopic contrast sensitivity improved from 0.175 log units (SD 0.108) to 0.128 log units (SD 0.124) (p<0.001), and scotopic contrast sensitivity improved from 0.340 log units (SD +/– 0.114) to 0.224 log units (SD +/– 0.104) (p<0.001).
Mesopic and scotopic contrast sensitivity improved significantly following LASEK in our study population. This result is in stark contrast to the majority of the current refractive literature, which has demonstrated no improvement or a reduction in contrast sensitivity following refractive procedures (LASIK or PRK). To date, few papers have discussed LASEK and it’s effect on contrast sensitivity. It is our contention that the improvement in contrast sensitivity is due to the use of a prolate ablation profile with surface laser (LASEK).
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