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Comparing PRK, Microkeratome LASIK, and IntraLASIK for Correction of Post Radial Keratotomy Refractive Errors. PERRY S. BINDER, MS MD* San Diego, California. *Dr. Binder is a paid consultant to Abbott Medical Optics, Inc. and is Owner of Outcomes Analysis Software.
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Comparing PRK, Microkeratome LASIK, and IntraLASIK for Correction of Post Radial Keratotomy Refractive Errors PERRY S. BINDER, MS MD* San Diego, California *Dr. Binder is a paid consultant to Abbott Medical Optics, Inc. and is Owner of Outcomes Analysis Software
Purpose: To evaluate three approaches to treat post-radial keratotomy refractive errors: Surface Ablation, Mechanical Microkeratome LASIK, Femtosecond LASIK (IntraLASIK). Methods: One surgeon. Retrospective database analysis of 105 eyes that received one of the three approaches: PRK (27 eyes), microkeratome LASIK (MK) (49 eyes), IntraLASIK (IL) (29 eyes). PRK performed with out MMC; mechanical MK and IntraLase w 160 um attempted flap thickness. Results: 51 eyes w Hyperopic astigmatism: All 3 had improved UCVA and slight loss of 1-2 lines of BSCVA. PO MRSE was -0.21, -0.46 and -0.88 for PRK, MK, IL. Increase in Mean K was 1.45 D, 1.12 D and 3.06 IL. 34 w myopic astigmatism:Smallest loss of BSCVA w IL. PO MRSE was -0.41 D, -0.51 D, and -0.46 D for PRK, MK, and IL. Reduction in Mean K was 0.53 D, 0.73 D, and 2.04 D respectively. “Pizza pie” in 7 MK and 2 IL cases. Enhancements more difficult for LASIK cases. Conclusions: All three procedures had a loss of 1-2 lines of BSCVA but significant improvement in UCVA with similar refractive errors; greatest change in Mean K with IL. PRK had best results for hyperopic astigmatism, IL for myopic astigmatism. No clear winner between these approaches based on analysis of a heterogeneous RK population (differences in time from RK to surgery, no. of incisions, original refractive errors, patient age, previous RK enhancements, etc.)
Methods • Excimer Lasers: Summit Apex Plus, LADARVision 4000, VISX S2-4, Allegretto 200 • Microkeratomes: ACS, SKBM, BD 4000 • 160 um flaps were attempted • Femtosecond Laser: IntraLase 10-60 kHz • 160 um flaps were attempted
Surgical Indications • Under or overcorrected RK/AK eyes >5 years after surgery • No external disease • No keratometry or pupil selection • No restriction based on BSCVA • No RK/AK wound epithelialization • Excluded cases with diurnal refractive change >1 D
Results: Eyes Operated Hyperopic Astigmatism Presented
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Complications • One slipped flap w SKBM MK • Three “Pizza Pie”: 2 MK, 1 IL • Enhancements: • PRK = 5 • MK = 7 • IL = 2
Conclusions: Treatment of Refractive Errors after RK • There are many variables in the PostOp RK eye to consider; a much larger series is required to stratify these variables • Similar improvement in Mean K, UCVA BSCVA, SphEq. • Greater Loss ≥ 2 Lines BSCVA w IL and MK vs PRK, but numbers too small to be statistically significant • PRK best ± 0.5 D for Hyperopic Cyl; IL best for Myopic Astigmatism • IL with fewest enhancements • No clear “Winner”