J Korean Ophthalmol Soc.  2007 Aug;48(8):1028-1035.

Comparison of Changes in Higher-order Aberrations between Conventional and Wavefront-guided LASEK

• Lee SM
• Lee MJ
• Kim MK
• Wee WR
• Lee JH

Abstract

PURPOSE: To evaluate the postoperative higher-order aberrations (HOAs) and factors affecting postoperative changes in HOAs in eyes that underwent wavefront-guided LASEK (laser-assisted subepithelial keratectomy), compared with the eyes that underwent conventional LASEK.
METHODS
We reviewed the medical records of 221 patients who had undergone LASEK or wavefront guided LASEK with VISX WaveScan and VISX Star S4 eximer laser by a single surgeon (427 total eye operations). We matched 29 eyes of the LASEK and the wavefront LASEK groups (58 eyes total) according to the guideline: preoperative refractive power differences must be within 1 diopter and preoperative root-mean-square (RMS) of total HOAs differences must be within 0.01 micrometer. Preoperative wavefront aberrations and two-months postoperative wavefront aberrations and associated factors were compared and analyzed.
RESULTS
Postoperative total HOAs, comas, and spherical aberrations increased significantly from 0.36+/-0.10 micrometer to 0.49+/-0.16 micrometer (p=.001), 0.21+/-0.09 micrometer to 0.31+/-0.14 micrometer (p=.003), and 0.03+/-0.10 micrometer to 0.10+/-0.20 micrometer (p=.043), respectively, in the conventional LASEK group. In the wavefront LASEK group, postoperative HOAs, comas, and spherical aberrations significantly increased from 0.36+/-0.10 micrometer to 0.46+/-0.14 micrometer (p=.004), 0.18+/-0.10 micrometer to 0.29+/-0.14 micrometer (p=.002), and 0.09+/-0.14 micrometer to 0.19+/-0.14 micrometer (p=.006), respectively. There were no significant differences in HOAs between the two groups. A strong negative correlation between preoperative total HOAs and a multiple of increase in total HOAs postoperatively was found, with the negative correlation being stronger in the wavefront-guided LASEK group (Pearson's correlation coefficient =-0.697, p<.001) than in the LASEK group (Pearson's correlation coefficient =-0.632, p<.001).
CONCLUSIONS
There were no significant decreases in HOAs in the eyes that underwent wavefront-guided LASEK compared with the matched control eyes of patients that underwent conventional LASEK. Analyzing the tendency of a multiple of increase in total HOAs according to the preoperative HOAs, it suggests that the wavefront-guided LASEK may be more effective in suppressing an increase in total HOAs in the eyes with higher preoperative HOAs.

Keyword

Case control study; Higher order aberrations; LASEK; Postoperative change; Wavefront

MeSH Terms

Case-Control Studies
Coma
Humans
Keratectomy, Subepithelial, Laser-Assisted*
Medical Records

Figure

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  Figure 1. Visual acuity change preoperatively and 2 months postoperatively. The visual acuity was converted to decimal form after calculation of mean and standard deviation with Log MAR visual acuity.

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  Figure 2. Wavefront aberrations acquired at 4 mm-sized pupil preoperatively and 2 months postoperatively. The values of total HOAs, coma, spherical aberration increased at postoperative 2 months compared with the preoperative values in the two groups, but the value of total HOAs, coma, trefoil, spherical aberration were not significantly different between the two groups preoperatively and 2 months postoperatively.

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  Figure 3. Difference in wavefront aberrations between preoperative value and postoperative 2 months value

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  Figure 4. Multiple of increase in total higer-order aberrations against preoperative total higher-order aberrations in conventional LASEK group and wavefront-guided LASEK group.

Reference

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