Topographically guided laser in situ keratomileusis for myopia using a customized aspherical treatment zone

Topography-Guided Versus Wavefront-Optimized LASIK for Myopia With and Without Astigmatism: A Meta-analysis

PURPOSE

To evaluate the differences in efficacy, predictability, safety, and visual quality between topography-guided customized ablation treatment (TCAT) and wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) for the treatment of myopia with and without astigmatism.

METHODS

A comprehensive literature search of PubMed, Embase, the Cochrane library, Web of Science, and ClinicalTrials was used to identify randomized controlled trials (RCTs) comparing TCAT-LASIK with WFO-LASIK for myopia with and without astigmatism up to September 2020. The references of all searched literature were checked as supplements. Literature was screened according to the inclusion and exclusion criteria and relative data were extracted. RevMan software version 5.3.0 (Cochrane Collaboration) was used for meta-analysis.

RESULTS

A total of seven RCTs (1,168 eyes) were included. There were no statistically significant differences in the ratio of uncorrected distance visual acuity of 20/20 or better (relative risk [RR] = 1.01, 95% CI [0.97 to 1.06], P = .64) and 20/16 or better (RR = 0.96, 95% CI [0.80 to 1.16], P = .69). Compared with WFO-LASIK, TCAT-LASIK achieved a higher proportion of postoperative manifest refractive spherical equivalent within ±0.50 diopters of the target (RR = 1.06, 95% CI [1.02 to 1.11], P = .003) and less surgically induced higher order aberrations (weighted mean difference [WMD] = -0.11, 95% CI [-0.15 to -0.0], P < .00001), spherical aberrations (WMD = -0.04, 95% CI [-0.05 to -0.03], P < .00001), and coma (WMD = -0.15, 95% CI [-0.28 to -0.01], P = .03). No patient lost two or more lines of distance-corrected visual acuity postoperatively in the two groups.

CONCLUSIONS

This meta-analysis suggests that both TCATLASIK and WFO-LASIK show excellent efficacy, predictability, and safety for myopia. TCAT-LASIK exhibited more accurate postoperative refraction predictability and less surgically induced higher order aberrations, spherical aberrations, and coma. More randomized, prospective, and large sample-sized studies are needed to confirm these conclusions in the long term. [J Refract Surg. 2021;37(10):707-714.].

Correction of Myopic Astigmatism with Topography-Guided Laser In Situ Keratomileusis (TOPOLINK)

We aim to assess the feasibility of topography-guided laser in situ keratomileusis (TOPOLINK) for correcting pre-existing and surgical-induced astigmatism. A retrospective, single center cohort study was conducted. Patients with pre-existing irregular myopic astigmatism were recruited into the primary group and those with irregular myopic astigmatism following laser in situ keratomileusis (LASIK) were recruited into the enhancement group. The changes in uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), maximum astigmatism, spherical equivalent (SE) and patient satisfaction were recorded. The Chi-square test, Mann-Whitney U test and Generalized Linear Mixed Model were utilized for the analysis in the current study. A total of 18 eyes were studied in the primary group and 14 eyes were examined in the enhancement group. One year postoperatively, the UCVA, BCVA, maximum astigmatism and SE improved significantly in both the primary and the enhancement groups (all p < 0.05). The UCVA (p = 0.046) and SE (p = 0.003) were worse in the primary group preoperatively but became similar in both groups postoperatively, while the BCVA and maximum astigmatism remained identical between groups throughout the study period (all p < 0.05). In addition, the rate of high and moderate satisfaction reached 90.0% in the primary and the enhancement groups, without significant differences (p = 0.871). In conclusion, the TOPOLINK showed high predictability and will contribute to similar outcomes between primary and postoperative irregular myopic astigmatism concerning visual acuity, refractive status and subject satisfaction.

Outcomes of topography-guided versus wavefront-optimized laser in situ keratomileusis for myopia in virgin eyes

PURPOSE

To compare the outcomes of topography-guided and wavefront-optimized treatment in patients having laser in situ keratomileusis (LASIK) for myopia.

SETTING

Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India.

DESIGN

Prospective contralateral-eye case study.

METHODS

Patients had topography-guided LASIK in 1 eye and wavefront-optimized LASIK in the contralateral eye using the Customized Refractive Surgery Master software and Mel 80 excimer laser. Refractive (residual manifest refraction spherical equivalent [MRSE], higher-order aberrations [HOAs]), and visual (uncorrected distance visual acuity [UDVA] and photopic and mesopic contrast sensitivity) outcomes were prospectively analyzed 6 months postoperatively.

RESULTS

The study comprised 35 patients. The UDVA was 0.0 logMAR or better and the postoperative residual MRSE was ±0.50 diopter in 94.29% of eyes in the topography-guided group and 85.71% of eyes in the wavefront-optimized group (P = .09). More eyes in the topography-guided group than in the wavefront-optimized group had a UDVA of -0.1 logMAR or better (P = .04). Topography-guided LASIK was associated with less deterioration of mesopic contrast sensitivity at higher spatial frequencies (12 cycles per degree [cpd] and 18 cpd) and lower amounts of induced coma (P = .04) and spherical aberration (P = .04). Less stromal tissue was ablated in the topography-guided group (mean 61.57 μm ± 16.23 [SD]) than in the wavefront-optimized group (mean 79.71 ± 14.81 μm) (P < .001).

CONCLUSION

Although topography-guided LASIK and wavefront-optimized LASIK gave excellent results, topography-guided LASIK was associated with better contrast sensitivity, lower induction of HOAs, and a smaller amount of tissue ablation.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Visual and Refractive Outcomes of Topography-guided Laser-assisted In Situ Keratomileusis in Virgin Eyes

Introduction

We wanted to assess the efficacy, predictability, and stability of topography-guided, laser-assisted in situ keratomileusis (TGL) on normal untreated eyes with a preoperative best corrected visual acuity (BCVA) of 20/20.

Methods

This was a retrospective, non-randomized, and single arm study evaluating the outcomes of TGL in eyes with a preoperative BCVA of 20/20. We included 50 eyes of 50 patients who presented to the Hashmanis Hospital, Pakistan and were followed for six months postoperatively. All eyes underwent treatment using the Alcon Wavelight Allegro Topolyzer (Alcon Laboratories, Inc., TX, USA).

Results

The mean preoperative sphere, cylinder, and spherical equivalent (SE) values were -4.3 ± 1.6 dioptres (D), -1.0 ± 0.8 D, and -4.8 ± 1.8 D. On day one these values were 0.2 ± 0.8 D, -0.5 ± 0.3, and  0.3 ± 0.8, respectively, and on month six they were -0.1 ± 0.6, -0.5 ± 0.3, and -0.4 ± 0.6 D, respectively. On postoperative day one and month six, 86% and 94% of eyes had a UCVA of 20/20 or better, respectively. Two eyes (4%) had an SE change of greater than 0.5 D from three to six months.

Conclusion

Our study demonstrates good efficacy, predictability, and stability of eyes undergoing TGL with a follow-up of six months.

Comparison and analysis of FDA reported visual outcomes of the three latest platforms for LASIK: wavefront guided Visx iDesign, topography guided WaveLight Allegro Contoura, and topography guided Nidek EC-5000 CATz

Purpose

To compare and analyze the differences in visual outcomes between Visx iDesign Advanced WaveScan Studio™ System, Alcon Wavelight Allegro Topolyzer and Nidek EC-5000 using Final Fit™ Custom Ablation Treatment Software from the submitted summary of safety and effectiveness of the US Food and Drug Administration (FDA) data.

Methods

In this retrospective comparative study, 334 eyes from Visx iDesign, 212 eyes from Alcon Contour, and 135 eyes from Nidek CATz platforms were analyzed for primary and secondary visual outcomes. These outcomes were compared via side-by-side graphical and tabular representation of the FDA data. Statistical significance was calculated when appropriate to assess differences. A P-value <0.05 was considered statistically significant.

Results

The mean postoperative uncorrected distance visual acuity (UDVA) at 12 months was 20/19.25±8.76, 20/16.59±5.94, and 20/19.17±4.46 for Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. In at least 90% of treated eyes at 3 months and 12 months, all three lasers showed either no change or a gain of corrected distance visual acuity (CDVA). Mesopic contrast sensitivity at 6 months showed a clinically significant increase of 41.3%, 25.1%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively. Photopic contrast sensitivity at 6 months showed a clinically significant increase of 19.2%, 31.9%, and 10.6% for eyes using Visx iDesign, Alcon Contoura, and Nidek CATz, respectively.

Conclusion

FDA data for the three platforms shows all three were excellent with respect to efficacy, safety, accuracy, and stability. However, there are some differences between the platforms with certain outcome measurements. Overall, patients using all three lasers showed significant improvements in primary and secondary visual outcomes after LASIK surgery.

Optical quality and visual discrimination capacity after myopic LASIK with a standard and aspheric ablation profile

PURPOSE

To determine whether the eye's optical quality is correlated to the visual discrimination capacity of patients treated with LASIK using two different ablation algorithms.

METHODS

Visual discrimination was evaluated by the disturbance index under low illumination (Halo v1.0 software, Laboratory of Vision Sciences and Applications) in two groups of patients who underwent LASIK with two different ablation algorithms using the Allegretto Wave Eye-Q 400 Hz laser (WaveLight AG). In the first group (standard group; 30 eyes), corneal ablations were performed with the standard algorithm (preoperative spherical equivalent refraction -3.20±1.70 diopters [D]). In the second group (Q-optimized group; 38 eyes; spherical equivalent refraction -3.40±1.90 D), the ablations were made with the Q-optimized (F-CAT) algorithm. Optical quality of the eye was calculated by the Strehl ratio measured with a double-pass device (OQAS, Visiometrics SL).

RESULTS

After LASIK, both the Strehl ratio as well as visual discrimination capacity diminished in both groups, although the changes were significantly greater in the standard group than in the Q-optimized group.

CONCLUSIONS

A high correlation was found between the Strehl ratio and the disturbance index in patients who underwent LASIK, regardless of the ablation algorithm applied. Optical and visual deterioration were greater after standard ablation.

Visual performance after LASIK for a Q-optimized and a standard ablation algorithm

We test visual performance after LASIK (laser in situ keratomileusis) for a Q-optimized ablation algorithm and one based on the Munnerlyn formula. The visual functions tested include aberrometry, monocular and binocular contrast sensitivity function (CSF), and a discrimination test under low-illumination conditions. This test is useful to quantify night-vision disturbances. A total of 102 patients took part in the experiments, and visual data were taken before (with best correction) and after LASIK. Results show a deterioration in aberrometry, CSF, binocular summation, and discrimination index for the two algorithms tested, although this deterioration is significantly lower for the Q-optimized algorithm.