Observation of corneal wavefront-guided FS-LASIK in the treatment of myopia with different degrees of astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the postoperative efficacy of corneal wavefront-guided femtosecond laser-assisted excimer in situ keratomileusis(FS-LASIK)in the treatment of myopia patients with different degrees of astigmatism and the changes of corneal higher order aberration.METHODS: A total of 133 patients(265 eyes)with myopia and astigmatism were enrolled in this retrospective study. All of them underwent corneal wavefront-guided FS-LASIK surgery for the first time in Aier Eye Hospital(Kunming)from April to October 2020. The patients were divided into three groups according to the different astigmatism: Low astigmatism group: astigmatism ≤1.0D, 62 cases(124 eyes), medium astigmatism group: a total of 54 cases(107 eyes)with astigmatism was 1.25-2.0D, high astigmatism group: a total of 17 cases(34 eyes)with astigmatism ≥2.25D. Visual acuity and refraction were recorded before surgery and 3mo after the surgery and the cornea of the patients was measured by Pentacam three-dimensional corneal topography. Record total higher order aberrations(root mean square), spherical aberration, horizontal coma, vertical coma, horizontal clover and oblique clover in the 6mm diameter range of the cornea. The postoperative effects of the three groups of patients were observed and the changes of corneal high order aberration before and after surgery were compared. RESULTS: The validity index of visual acuity in the three groups of patients was all greater than 1.1 and the residual diopter was all within ±0.30D. The residual diopter in the low astigmatism group was the least than that of the other two groups(P<0.05). At 3mo after surgery, the corneal total higher order aberration, spherical aberration and vertical coma of the three groups were all increased compared with those before surgery(P<0.05). The spherical aberration increase in the high astigmatism group was less than that in the other two groups(P<0.05).CONCLUSION: Corneal wavefront-guided FS-LASIK surgery is safe and effective in the treatment of myopia with different degrees of astigmatism, and the effect is also accurate for patients with high astigmatism. The degree of of preoperative astigmatism is not responsible for increased corneal higher order aberration after the surgery.

Changes in higher order aberrations after wavefront guided FS-LASIK for myopia combined with moderate to high astigmatism / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To assess the changes in higher order aberrations after wavefront guided femtosecond laser assisted laser in situ keratomileusis ( FS-LASIK ) for moderate to high astigmatism.?METHODS: Eighty-eight eyes of 50 myopia patients with moderate to high astigmatism were included in this prospective study. There were 51 eyes with moderate astigmatism (≥-1. 50D and <-3. 00D) and 37 eyes with high astigmatism (≥-3. 00D). All patients underwent wavefront guided FS-LASIK. Uncorrected distance visual acuity ( UDVA ) , corrected distance visual acuity (CDVA), keratometry, central corneal thickness ( CCT)and higher order aberrations ( HOAs ) were evaluated before operation and 3mo postoperatively.?RESULTS:At the 3mo after operation, the mean UDVA of all eyes was above 20/20, better than before operation (P<0. 05), but CDVA remained unchanged (P=0. 36) and no eyes lost ≥2 lines of CDVA. Mean astigmstism of 85 eyes ( 97％) was reduced below - 1. 00D, mean astigmatism of 70 eyes ( 80％) was reduced below-0.50D(P<0. 05). The average corneal curvature was flatter by 3. 81 ± 1. 97D and CCT was reduced by 78. 66 ± 37. 22μm, postoperatively (P<0. 05). Coma and trefoil aberrations remained unchanged(P=0. 078, 0. 065). The spherical aberration, secondary astigmatism and the HOA root mean square ( RMS ) increased from 0. 19 ± 0. 06, 0.05±0. 02 and 0. 42±0. 12, preoperatively to 0. 32± 0. 17, 0. 26 ± 0. 08 and 0. 78 ± 0. 28 ( P < 0. 05 ), postoperatively.?CONCLUSION: Wavefront-guided FS-LASIK is a safe and effective option for the patients with moderate to high astigmstism although parts of HOAs increased.

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.

Higher-Order Aberrations and Visual Acuity with Wavefront-Guided and Wavefront-Optimized Ablation in Laser Keratorefractive Surgery

PURPOSE: To compare higher-order aberrations (HOAs) and visual acuity after wavefront-guided and wavefront-optimized laser keratorefractive surgery. METHODS: This retrospective study consisted of consecutive cases of eyes that underwent wavefront-guided (VISX S4 CustomVue(R)) or wavefront-optimized (WaveLight(R) EX500) laser assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK). Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction spherical equivalent (MRSE), and preoperative and 3 month postoperative HOAs were compared. RESULTS: There were no statistical differences in UCVA, BCVA, MRSE, or total HOAs in either the LASIK and PRK groups (all p > 0.05). Induced amount of spherical aberration (SA) was significantly lower in the wavefront-optimized LASIK and PRK than wavefront-guided LASIK and PRK. CONCLUSIONS: In laser keratorefractive surgery, wavefront-guided and wavefront-optimized platforms produced equivalent visual outcomes and no differences in total HOAs. However, the wavefront-optimized platform caused less spherical aberration 3 months after operation.

Contrast to wavefront optimized and wavefront guided excimer laser photorefractive keratectomy / 中华实验眼科杂志

Conventional excimer laser keratectomy have been proved to achieve better visual function,but the traditional therapy of corneal spherical cutting line generally flat profile will make the cornea more oblate shape and the contours of the cornea and lcad to spherical aberration.The alteration of non.spherical nature cause the increase of corneal spherical aberration,which further affects the night vision and contrast sensitivity and other visual quality.Wavefront optimization based on total number of adjustments are to retain the previous visual aberrations of eyes and optimize the non-spherical nature of cornea to create a ideal model based on individual adjustments.Ocular wavefront-guided measurement and ablation in exeimer laser keratectomy can achieve better visual outcome.In this paper,wavefront guided and wavefront optimized treatment outcome for the spherical aberration correction are reviewed.

Visual outcomes and higher-order aberrations of wavefront vs. combined wavefront aspheric

Objective@#We compared the efficacy, safety, refractive and visual outcomes, and aberrometry results of wavefront-guided aspheric treatment (WTA) versus wavefront-guided treatment (WT).@*Methods@#This prospective, contralateral, comparative study included 60 eyes of 30 patients who underwent myopic LASIK. One eye of each patient was randomized to either WTA or WT. Patients were followed up for 3 months postoperatively. Two-tailed paired t-test was used to determine statistical significance.@*Results@#At 3 months, 93% of eyes in the WTA group and 83% in the WT group had high-contrast uncorrected distance visual acuity (UDVA) of 20/20, while 87% in both groups achieved low-contrast UDVA of 20/40 or better. Sixty-four percent in the WTA gained 1 or more lines of low-contrast corrected distance visual acuity (CDVA) compared to 50% in the WT group. The mean sphere was 0.17D in the WTA and 0.14D in the WT (p = 0.63). The mean spherical equivalent was –0.04D for WTA and –0.03D for WT (p = 0.88). All eyes in both groups were within ±1.00D of the target emmetropia. The mean change in total higher-order aberration (HOA) was 0.07 μm in the WTA compared to 0.15 μm in the WT group (p = 0.04). The mean change in spherical aberration was –0.01 μm in the WTA and 0.18 μm in the WT group (p < 0.001). The mean change in Q value was significantly lower in the WTA (0.31) than in the WT group (0.63) (p < 0.001).@*Conclusion@#Wavefront aspheric LASIK (WTA) is a safe and effective treatment for myopic astigmatism. Refractive and visual outcomes were similar for both groups. WTA had less induction of higher-order aberration, lower spherical aberration, and better preservation of corneal asphericity (Q value). This translated to more lines of low-contrast vision gained compared to WT. Keywords: LASIK, Wavefront-guided, Aspheric, Spherical aberration, higher-order aberration, Corneal curvature

Considering Spherical Aberration in Choosing the Wavefront Map for Laser Vision Correction

PURPOSE: To report the dynamic nature of human optical aberrations in the scotopic condition. METHODS: A total of 20 eyes who were candidates for laser vision correction were included in the present study. Repeated wavefront data were obtained using WavescanTM (AMO/VISX). From the wavefront analysis data, the sphere, astigmatism, average pupil size, spherical aberration, coma and trefoil were selected and used to investigate any correlation among the parameters. RESULTS: The sphere, spherical aberration, coma and pupil size showed a dynamic change in the scotopic condition. The spherical aberration and pupil size decreased by the amount of 0.10 +/- 0.04 microm and 0.55 +/- 0.37 mm as the sphere changed 1 D in myopic direction. There was significant positive correlation between the sphere and spherical aberration in 13 eyes of 9 patients (65%), between the sphere and pupil size in 5 eyes of 4 patients (25%), and between the sphere and coma in 3 eyes of 3 patients (15%). The spherical aberration decreased significantly in 4 eyes of 4 patients (20%) as the pupil size decreased. CONCLUSIONS: The optical aberration of human eyes showed a dynamic nature in the scotopic condition. In particular, there was significant correlation between the sphere and spherical aberration. The observed correlations have the potential to be used as helpful indicators to select the optimal wavefront data for the laser vision correction.

Comparison of the Refractive Error Measurement Using Different Methods in Wavefront-Guided LASEK

PURPOSE: To predict the accuracy of preoperative refractive error measurement methods in wavefront-guided laser-assisted subepithelial keratectomy (LASEK) surgery and to formulate a nomogram for satisfactory surgical results. METHODS: The medical records of 30 patients (57 eyes) who had undergone wavefront-guided LASEK were reviewed. The ideal surgical ablation amount was defined as the sum of the real surgical ablation amount and the remaining refractive errors. Comparison between the ideal surgical ablation amount and preoperative refractive errors was made using autorefraction, manifest refraction, cycloplegic refraction, postcycloplegic refraction, wavescan, and iTrace aberrometer measurements. RESULTS: The refractive errors measured by the postcycloplegic refraction showed the closest relation with the ideal surgical amount, and the nomogram based on this refraction correlated statistically significantly with the ideal surgical ablation amount. The refractive error using the wavescan also showed more accurate refractive measurements than the autorefractor and iTrace aberrometer. CONCLUSIONS: Accurate manifest refraction immediately before surgery is the most important in determining the ablation amount. Additionally, the refractive errors measured with the wavescan, which is an aberrometer used for wavefront-guided LASEK, showed a minimal amount of errors. After reviewing the results, the nomogram based on these 2 methods can be concluded to possibly contribute to an increase in the accuracy of surgery.

Clinical Outcomes of Wavefront-Guided Epi-LASIK: 6-Months Follow-up

PURPOSE: We evaluate the clinical outcomes after wavefront-guided (WFG) Epi-LASIK in mild and moderate myopia . METHODS: The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, total high order aberrations, contrast sensitivity for day and night vision, and pain score in 114 eyes of 61 patients who had undergone WFG Epi-LASIK were measured preoperatively and at 1 day, 1 week, 1 month, 2 months, and 6 months postoperatively. RESULTS: At 1 day, 1 week, 1 month, 2 months and 6 months postoperatively, UCVA & BCVA had improved significantly. At 1 month postoperatively, the spherical equivalent was -0.93+/-0.74 and showed a stable pattern at 6 months postoperatively. There was no statistically significant difference in total high-order aberration between preoperatively measurements and measurements taken at 6 months postoperative (p=0.745). At a frequency of 19 cpd, night contrast sensitivity showed significant statistical difference (p=0.010) but no difference at low and medium frequencies between preoperative measurements and postoperative six months measurements. Pain subsided at 2 weeks postoperative. All patients maintained clear cornea and suffered no complications. CONCLUSIONS: At 6 months postoperatively, patients who underwent Wavefront-guided Epi-LASIK showed successful results for the correction of moderate myopia and excellent contrast sensitivity at night time. Wavefront-guided Epi-LASIK may solve the visual quality problem after refractive surgery and, therefore, may be clinically useful.

The Changes of Posterior Corneal Surface and High-Order Aberrations after Refractive Surgery in Moderate Myopia

PURPOSE: To compare forward shift of posterior corneal surface and higher-order aberration (HOA) changes after LASIK, LASEK, and wavefront-guided LASEK surgery in moderate myopia METHODS: One hundred eighty four eyes undergoing LASIK, LASEK and wavefront-guided LASEK with VISX STAR S4 were included in this study. The posterior corneal elevation was measured with Orbscan before, 2 and 4 months after surgery. Changes of the elevation were assessed using the difference map generated from preoperative and postoperative elevation maps. The values of higher-order aberrations were evaluated preoperatively and 2 months postoperatively with Wavefront aberrometer. RESULTS: The posterior corneal surface displayed forward shift of 27.2+/-11.45 micrometer, 24.3+/-9.76 micrometer in LASIK group, 23.4+/-10.5 micrometer, 23.6+/-10.55 micrometer in LASEK group, 24.0+/-14.95 micrometer, 28.4+/-14.72 micrometer in wavefront-guided LASEK group at 2 months and 4 months, respectively. There were no statistically significant differences among those three groups, and between 2 and 4 months. The root mean score (RMS) of HOA was increased after LASIK and LASEK (p=0.000, p=0.000, respectively). The mean change of HOA-RMS was significantly smaller in wavefront-guided LASEK than LASIK or LASEK (p=0.000, p=0.000, respectively, Bonferroni-corrected). CONCLUSIONS: The changes of posterior corneal surface forward shift showed no difference among LASIK, LASEK and wavefront-guided LASEK in moderate myopia. HOAs were significantly increased after LASIK and LASEK. The changes of HOAs were significant smaller in wavefront-guided LASEK than LASIK or LASEK.

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.