1. PERRY S. BINDER, MS MD* San Diego, California
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

2. 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, and 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 D, D, and 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.)

3. 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 kHz

4. 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

5. Results: Eyes Operated Hyperopic Astigmatism Presented
Total
Eyes
Hyperopic
Astigmatism
Myopic
Hyperopia
Myopia
PRK 27 18 7 1
MK LASIK 49 21 15 6 5
IntraLase
LASIK 29 12 3
Totals
105 51 34 8 9

6. Smaller is better

7. Smaller is better

8. Steeper is better

9. % %

11. Complications One slipped flap w SKBM MK Three “Pizza Pie”: 2 MK, 1 IL
Enhancements:
PRK = 5
MK = 7
IL = 2

12. 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”