Wavefront-guided Versus Standard Laser in situ Keratomileusis in Myopia Using a 213 nm Wavelength Solid-state Laser: Comparison of Higher-order Aberrations.

Purpose: To assess the accuracy, efficacy, stability and safety of laser in situ keratomileusis (LASIK) for myopia and compare the pre- and post-operative changes in higher-order aberrations after wavefront-guided (WF) and standard (STD) LASIK done using the Pulzar Z1, a 213-nm wavelength solid-state laser, and determine their effects on visual acuity and refractive outcomes. Methods: This a retrospective case series composed of 80 eyes (40 patients) that had LASIK in an out-patient refractive surgery center in Manila, Philippines. Outcome measured were pre and post-operative manifest refraction spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (CDVA), keratometry, root-mean-square (RMS) values, flap and ablation related complications. Results: The mean UDVA improved from 20/400 pre-operatively to 20/25 post-operatively. Thirty six of the 40 eyes (90%) treated with STD LASIK and 39 of the 40 eyes (97.5%) treated with WF LASIK had UDVA of 20/30 or better at 1 year post-operatively. There was a significant decrease in spherical equivalent manifest refraction post-operatively in all patients. The average spherical equivalent at 1 year is -0.43D±0.64. After twelve months of follow-up, 85.5% (34 out of the 40 eyes) of those who underwent STD LASIK and 77.5% (31 out of 40 eyes) who underwent WF LASIK had postoperative manifest refractive spherical equivalent (MRSE) of -1.0 to +1.0D. The mean difference in the attempted versus achieved refraction was not significant between the 2 groups (p = 0.32). At 12 months post-operatively, seven eyes (17.5%) gained 1 line in the WF-guided LASIK, while the rest of the eyes either showed no change in CDVA or lost 1-2 Snellen lines. The total RMS generally increased postoperatively for WF LASIK while decreased for STD LASIK, but the mean RMS difference from the pre- and post-operative values between the 2 groups were not statistically significant. None of the eyes developed flap complications during the follow-up period. Conclusion: Refractive surgery using the Pulzar Z1 213-nm wavelength solid-state laser is an effective and safe procedure in the treatment of myopia. Wavefront-guided LASIK offers no advantage over STD LASIK in improving higher-order aberrations and in achieving better visual and refractive outcomes.

Clinical Outcomes of Wavefront-guided LASIK using the Fourier Algorithm: 6-Month Follow-up

PURPOSE: We evaluate the clinical outcomes after wavefront-guided LASIK using the Fourier algorithm. METHODS: The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction measured with auto refractometer, spherical aberration, coma, trefoil, total high order aberrations and contrast sensitivity of daytime and nighttime in 23 eyes of 13 patients who had undergone wavefront-guided LASIK using the Fourier algorithm preoperatively and at 1 day, 1 week, 1 month, 2 months and 6 months postoperatively. RESULTS In the wavefront-guided LASIK using the Fourier algorithm, the preoperative UCVA was 0.13+/-0.10 and increased to 1.02+/-0.29 (p=0.000) at 6 months postoperative, the postoperative spherical equivalent was -6.48+/-1.68D and 1.02+/-0.29 (p=0.000) at 6 months postopertive. The total high order aberration was 0.324+/-0.107 preoperative and 0.338+/-0.167 (p=0.810) at 6 months postoperative in wavefront-guided LASIK using the Fourier algorithm. Preoperative daytime contrast sensitivity increased preoperative from 0.75+/-0.24 to 1.11+/-0.35 (p=0.026) at 12 cpd, and that at 6-month preoperative increased from 1.05+/-0.26 to 1.41+/-0.41 (p=0.003) at 7.5 cpd and from 1.45+/-0.34 to 1.69+/-0.42 (p=0.028) at 4.8 cpd. CONCLUSIONS: The clinical outcomes of wavefront-guided LASIK using the Fourier algorithm after 6 months were stable visual acuity, no increase in high order aberration and no increase in contrast sensitivity.

Clinical Outcomes of Wavefront-guided LASIK using the Fourier Algorithm: 6-Month Follow-up

PURPOSE: We evaluate the clinical outcomes after wavefront-guided LASIK using the Fourier algorithm. METHODS: The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction measured with auto refractometer, spherical aberration, coma, trefoil, total high order aberrations and contrast sensitivity of daytime and nighttime in 23 eyes of 13 patients who had undergone wavefront-guided LASIK using the Fourier algorithm preoperatively and at 1 day, 1 week, 1 month, 2 months and 6 months postoperatively. RESULTS In the wavefront-guided LASIK using the Fourier algorithm, the preoperative UCVA was 0.13+/-0.10 and increased to 1.02+/-0.29 (p=0.000) at 6 months postoperative, the postoperative spherical equivalent was -6.48+/-1.68D and 1.02+/-0.29 (p=0.000) at 6 months postopertive. The total high order aberration was 0.324+/-0.107 preoperative and 0.338+/-0.167 (p=0.810) at 6 months postoperative in wavefront-guided LASIK using the Fourier algorithm. Preoperative daytime contrast sensitivity increased preoperative from 0.75+/-0.24 to 1.11+/-0.35 (p=0.026) at 12 cpd, and that at 6-month preoperative increased from 1.05+/-0.26 to 1.41+/-0.41 (p=0.003) at 7.5 cpd and from 1.45+/-0.34 to 1.69+/-0.42 (p=0.028) at 4.8 cpd. CONCLUSIONS: The clinical outcomes of wavefront-guided LASIK using the Fourier algorithm after 6 months were stable visual acuity, no increase in high order aberration and no increase in contrast sensitivity.

Change of High-order Aberration after Wavefront-guided LASIK and LASEK

PURPOSE: To evaluate the changes in ocular high-order aberration after wavefront-guided laser in situ keratomileusis (LASIK) and wavefront-guided laser-assisted subepithelial keratectomy (LASEK). METHODS: Twenty-four eyes of 14 patients who underwent wavefront-guided LASIK, and ten eyes of six patients who underwent wavefront-guided LASEK were retrospectively reviewed. Uncorrected visual acuity, best corrected visual acuity, manifest refraction and high order aberration were evaluated before the operation and at 1 week, 1 month, 2 months and 6 months after the operation. Aberrations were measured using a WaveScan Wavefront System (VISX, Santa Clara, CA). We analyzed the total high-order aberration, coma aberration and spherical aberration before and after surgery. RESULTS: There were no statistically significant differences in total high-order aberration or coma aberration between preoperative and postoperative 6 month measurements in either group. However the spherical aberration showed a statistically significant increase between the preoperative and postoperative 6 month measurements in the wavefront-guided LASEK group (p=0.037). The total high order aberration showed no correlation with the preoperative spherical equivalent (p=0.55), and the change in total high-order aberration did not correlate with the amount of surgically achieved correction in either group at all follow-up periods. CONCLUSIONS: Wavefront-guided LASIK and wavefront-guided LASEK showed no statistically significant changes in total high-order aberration at postoperative 6 months.

Clinical Outcomes of Wavefront-guided LASIK: 6-Months Follow-up

PURPOSE: To observe the result of wavefront-guided (WFG) LASIK and investigate the ocular high order aberrations of WFG LASIK compare with conventional LASIK. METHODS: The uncorrected visual acuity (UCVA), manifest refraction, total high order aberration, coma and spherical aberration in 22 eyes of 13 patients who had undergone WFG LASIK were measured preoperative and at 1, 3 and 6 months postoperatively. The ocular high order aberrations of 19 eyes from 11 patients who had undergone convetional LASIK were measured at 6 months after surgery. The ocular high order aberrations of the WFG LASIK and conventional LASIK groups were compared. RESULTS: In the WFG LASIK group, the UCVA and spherical equivalent increased from 0.06 to 1.08 and from -6.13D to -1.16D, respectively after 6 months. The total high order aberration and coma (RMS) were 0.40 and 0.31 in conventional LASIK and 0.28 and 0.16 in WFG LASIK after 6 months. There was a statistically significant difference (p<0.05). CONCLUSIONS: The clinical outcomes of wavefront-guided LASIK by 6 months were a stable improvement in the visual acuity and a correction of all the optical aberrations of the eye. The postoperative high order aberration was significantly smaller than that in the conventional LASIK group.