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J. T. Holladay; Modulation Transfer Function and the Correction of Higher Order Aberrations With Two Different Laser Systems. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4210.
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© ARVO (1962-2015); The Authors (2016-present)
To measure the impact on postoperative quality of vision of two different approaches to correcting higher-order aberrations (HOA) in laser vision correction (LVC).
Charts for 211 eyes undergoing laser vision correction were retrospectively reviewed. All flaps were made with an IntraLase femtosecond laser. Approximately half the eyes (102) received Wavelight wavefront-optimized treatments (WFO), while the other half (109) received Visx CustomVue wavefront-guided treatments (WFG) with iris registration. The treatment range was similar between groups. HOAs over 4.00-mm and 6.00-mm zones, including separate measures of spherical aberration, coma, and trefoil, were analyzed pre- and post-operatively in all eyes in both groups. UCVA & BSCVA were measured at high (98%) and low (5%) contrast and cross-analyzed by the modulation transfer function (MTF), a measure of optical image quality.
Mean total HOA increased in the WFO group from 0.29 preop to 0.42 ± 0.27 postop, and decreased in the WFG group, from 0.29 preop to 0.27 ± 0.15 postop. HOAs were the same or better in 59% and worse in 41% of eyes in the WFO group. In the WFG group, HOAs were the same or better in 88% and worse in only 12% of eyes. The areas under the 4.0-mm and 6.0- mm MTF were significantly different at 0.67 ± 0.14 and 0.25 ± 0.07 for WFG and 0.58 ± 0.14 and 0.21 ± 0.06 for WFO (p < 0.001). Lower total HOA and higher MTF correlated with better high- and low-contrast acuity.
WFG procedures are much less likely than WFO procedures to worsen higher-order aberration. The areas under the 4.00-and 6.00-mm MTF were significantly better in the WFG group, demonstrating that WFG LASIK with a femtosecond laser flap produces better quality of vision than wavefront-optimized LASIK.
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