13
LASEK Enhancements
Lee Shahinian, Jr, MD
Stanford University
Stanford, CA
LASEK ENHANCEMENTS
With the increasing use of laser-assisted subepithelial keratectomy (LASEK) to correct a wide range of refractive errors (1–6), it is important to determine the technique, safety, and efficacy of enhancements.
Study Design
Six surgeons contributed data to this study: Thomas Claringbold, Daniel Durrie, Jorge Muravchik, Woo Jin Sah, Steven Schaller, and Lee Shahinian. Twenty-one eyes of 16 patients were included in this retrospective survey analysis. The primary procedure was LASEK in all cases. Average age was 41 years (range 24–58). Before enhancement, 16 eyes were myopic and four eyes were hyperopic. The average time from primary procedure to enhancement was 10 months (3–26 months). Average follow-up after enhancement was 5.6 months (1–12 months).
The six surgeons used a variety of excimer lasers. Nine eyes were treated with the Visx S2, five with the B&L, three with the Visx S3, three with the Lasersight, and one with the Nidek EC5000.
Surgical Technique
The surgical technique was identical to the primary procedure. A 20% alcohol solution was applied for an average of 37 seconds (10–50) for the enhancement vs. 36 seconds (25–45) for the primary procedure. In eight of 21 eyes, it was more difficult to lift the central portion of the epithelial flap in the area of previously ablated stroma.
Results
For the hyperopic eyes, mean preoperative spherical equivalent (SE) was +1.44 diopters (D), and mean postoperative SE was −0.12 D. For the myopic eyes, mean preoperative SE was −1.09 D, and mean postoperative SE was +0.07 D.
*Presented at the First International LASEK Congress, Houston, Texas, March 22, 2002.
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LASEK Enhancements |
153 |
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Table 1. Postoperative Uncorrected Visual Acuity |
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After LASEK Enhancement. |
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UCVA |
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n |
% |
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20/15 |
2 |
9.5 |
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≥20/20 |
12 |
57 |
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≥20/25 |
18 |
86 |
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≥20/30 |
20 |
95 |
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≥20/40 |
21 |
100 |
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Figure 1 After LASEK enhancement, the uncorrected visual acuity (UCVA) showed a shift to the left, indicating improved visual acuity after surgery.
Table 2. Gain and Loss of BSCVA After LASEK and LASEK Enhancements.
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Overall Change After LASEK and |
Post-LASEK Change After |
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Enhancement n (%) |
Enhancement n (%) |
Loss of 1 |
3 (14) |
3 (14) |
line |
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No change |
15 (72) |
14 (67) |
Gain of 1 |
3 (14) |
3 (14) |
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LASEK, PRK, and excimer laser stromal surface ablation |
154 |
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|
|
line |
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Gain of 2 |
0 |
1 (5) |
lines |
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Total eyes |
21 |
21 |
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Postoperatively, 57% of eyes had uncorrected visual acuity (UCVA) of 20/20 or better, 95% were 20/30 or better, and 100% were 20/40 or better (Table 1).
Figure 1 shows the dramatic improvement in UCVA after enhancement. Table 2 demonstrates that there was no significant gain or loss of best-corrected visual acuity (BCVA). One eye developed 2+ haze 1 month after enhancement. UCVA and BCVA were 20/25 at that time.
In the eight eyes (38%) in which the surgeon reported difficulty in lifting the central portion of the epithelial flap, the average interval between enhancement and primary procedure was 9.6 months. This was not significantly different than the corresponding interval (9.1 months) for the remaining eyes.
CONCLUSIONS
With the exception of postoperative haze in one eye, LASEK enhancement after primary LASEK appears to be safe and effective in a small pooled series. The epithelium is often more adherent over the area of previous stromal ablation. Longer follow-up on more eyes is needed to determine the incidence and severity of stromal haze after LASEK enhancement.
REFERENCES
1.Camellin M, Cimberle M. LASEK may offer the advantages of both LASIK and PRK. Ocular Surgery News, 1999; March: 28.
2.Shah S, Sebai Sarhan AR, Doyle SJ. The epithelial flap for photorefractive keratectomy. Br J Ophthalmol; 2001; 85:393–396.
3.Claringbold T. Laser assisted subepithelial keratectomy for the correction of myopia. J Cataract Refract Surg; 2002; 28:18–22.
4.Azar DT, Ang RT, Lee JB, Kato T, Chen CC, Jain S, Gabison E, Abad J. Laser subepithelial keratomileusis: electron microscopy and visual outcomes of flap photorefractive keratectomy. Curr Opin Ophthalmol; 2001; 12(4):323–328.
5.Lee JB, Seong GJ, Lee JH, Seo KY, Lee YG, Kim EK. Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia. J Cataract Refract Surg; 2001; 27(4):565–570.
6.Shahinian L. Laser-assisted subepithelial keratectomy for low to high myopia and astigmatism. J Cataract Refract Surg; 2002; 28(8):1334–1342.