1. Wavefront Optimized Retreatment after Prior Wavefront
Customized LASIK for Myopia
Juan C. Arciniega, MD; Engy Mohamed, MD; James P. McCulley, MD, FRCOphth (UK);
Wayne Bowman, MD.
Department of Ophthalmology, The University of Texas Southwestern Medical Center at Dallas, Texas. USA.
Financial Disclosure:
JCA and EM have no financial interest to disclose.
JPM and WB are consultants of Alcon Inc.
This study was supported in part by grants NIH EY12430, EY and an unrestricted grant from the Research to Prevent Blindness, New York, New York.

2. Background
Laser in situ keratomileusis (LASIK) is a popular technique for correcting myopia, myopic astigmatism, and mild to moderate hypermetropia.
Although the predictability is high, undercorrection and/or regression is inevitable in some eyes.1,2
Re-treatments may be necessary and useful to refine the results obtained after the first surgery. 2
Perez-Santonja JJ, Bellot J, Claramonte P, Ismail MM, Alio JL. Laser in situ keratomileusis to correct high myopia. J Cataract Refract Surg 1997;23:
O’Doherty M. O’Keeffe M, Kelleher C. Five year follow-up of laser in situ keratomileusis for all levels of myopia. Br J Ophthalmol 2006;90:20-3.

3. Purpose
To assess the visual outcomes, refractive error, and safety of Wavefront-Optimized (WFO) LASIK retreatment after previous Wavefront- Customized (WFC) LASIK in myopic patients.

4. Methods
A retrospective chart review of 18 eyes from 13 patients whom underwent WFO LASIK retreatment after previous WFC LASIK was performed.
All primary LASIK procedures were done using the Visx CustomVueTM laser platform (Abbott Medical Optics, Illinois, USA).
All eyes underwent LASIK retreatments using the Wavelight AllegrettoTM Eye-Q 400 excimer laser platform (Alcon Inc., Hünenberg, Switzerland).
Ophthalmic examinations, including uncorrected visual acuity (UCVA), best-spectacle corrected visual acuity (BSCVA), refractive error (RE), and complications were performed preoperatively and postoperatively at 1, 3, and 6 months.
Pre-retreatment total root mean square (RMS) from third to sixth order- Zernike polynomials was calculated.

5. Results
Pre-retreatment total high order aberrations (HOA).

6. Pre-operative and post-operative values of RE
Results
Table 1.
Pre-operative and post-operative values of RE
Pre-operative
POM 1
POM 3
POM 6
Spherea
-0.56±1.4
-0.31±0.5
-0.24±0.36
-0.39±0.35
Range
-3.0 to 1.5
-1.25 to 0.5
-1.25 to 0.25
-1.5 to 0
Astigmatisma
0.7±0.5
0.14±0.29
0.17±0.24
0 to 2
0 to 0.75
POM= Post-operative month. aValues expressed as mean ± standard deviation.

7. Results
Comparison between Pre-operative and Post-operative values of RE.

8. UCVA, BSCVA and SE over follow-up time
Results
Table 2.
UCVA, BSCVA and SE over follow-up time
Preoperative
POM 1
POM 3
POM 6
UCVA
0.27±0.16
0.062±0.12
0.06±0.12
0.02±0.05
BSCVA
0.01±0.03
-0.01±0.03
-0.03±0.05 SE
-0.211±1.4
-0.23±0.4
-0.16±0.29
-0.30±0.29
POM = postoperative month; UCVA = uncorrected visual acuity; SE = spherical equivalent
BSCVA = best spectacle corrected visual acuity; UCVA & BSCVA = logMAR scale

9. Results
Comparison between Pre-operative BSCVA and Post-operative UCVA at 6 months

10. Results
Pre-retreatment spherical equivalent changed from ± 1.4 D (range from 1.63 to -3.0) to ± 0.3 D (range from 0 to -1.0) at 6 months.

11. Results
The pre-retreatment total HOA was 0.48±0.21 (0.24 to 1.01µm) and did not show correlation with the visual outcomes postoperatively.
At 6 months all eyes were within ±0.50D of target refraction.
The efficacy index (UCVA post-operative/BSCVA pre-operative) was 1.0 at 6 months.
The safety index (BSCVA post-operatively/BSCVA pre-operatively) was 1.08 at 6 months.
No intraoperative or postoperative complications were reported.

12. Conclusion
Our findings suggest that Wavefront-Optimized ablation retreatment after primary Wavefront-Customized LASIK is safe and predictable, with positive visual and refractive outcomes achieved at 6 months post-treatment.
In addition, no correlation between the degree of pre-retreatment total RMS and visual outcomes postoperatively was detected.