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. Author manuscript; available in PMC: 2015 Mar 1.
Published in final edited form as: Cornea. 2014 Mar;33(3):280–287. doi: 10.1097/ICO.0000000000000050

Table 4.

Differences measured by OCT between the preoperative central and peripheral mean epithelial thicknesses, the nominal and actual laser ablation depths, and laser ablation efficiency of the VISX laser in PTK mode.

Center Periphery p
Mean epithelial thickness 60 ± 11 μm (range 55 to 78) 58 ± 9 μm (range 44–71) ns
Mean nominal laser ablation depth 113 ± 36 μm (range 75 to 177) 103 ± 50 μm (range 62–183) <0.05
Mean actual laser ablation depth 142 ± 34 μm (range 75 to 187) 140 ± 49 μm (range 62 to 185) <0.05
Mean difference between nominal and actual laser ablation depths 28 ± 30 μm (range −23 to 65) 16 ± 20 μm (range −15 to 38) ns
Laser ablation efficiency 120% 126% <0.00001