Topography-guided Laser In Situ Keratomileusis Research Articles

Fitting-Shape-based Strategy for Topography-guided LASIK: A Prospective Study.

To assess and compare the visual acuity and refractive outcomes of topography-guided laser in situ keratomileusis (LASIK) based on the fitting-shape-based refractive compensated and Phorcides software strategies. Consecutive patients who underwent topography-guided LASIK were included in this study. Through double-masked simple randomization, patients were assigned to the Zhang & Zheng Auto-compensate Refraction (ZZ AR) group (the fitting-shape-based refractive compensated strategy using the ZZ AR calculator was used) or the Phorcides group (the topography analysis algorithm in Phorcides software [Phorcides LLC] was used). Only one eye per patient with binocular correction was randomly enrolled. The preoperative and postoperative visual acuities and refraction were analyzed at the 6-month follow-up visit. The ZZ AR and Phorcides groups comprised 156 and 147 eyes, respectively. At the 6-month postoperative follow-up visit, the median (range) absolute residual cylindrical refraction was 0.35 (1.01) and 0.47 (1.63) diopters (D) for the ZZ AR and Phorcides groups, respectively (P < .001). The percentages of patients with residual cylindrical power within 0.25 D were 29.49% and 13.61% for the ZZ AR and Phorcides groups, respectively (P = .001). Based on the percentages of patients with residual cylindrical powers within 0.50 and 1.00 D, the ZZ AR group showed better outcomes (P = .02 and .01). The percentage of patients with visual acuity better than 20/16 was significantly higher for the ZZ AR group than for the Phorcides group (P = .03). The fitting-shape-based refractive compensated strategy for topography-guided LASIK procedures can better optimize the visual acuity and astigmatic refraction than the Phorcides software strategy. [J Refract Surg. 2024;40(5):e336-e343.].

Higher-Order Aberrations of Topography-Guided LASIK and Wavefront-Optimized LASIK in High- and Low-Myopic Eyes: A Non-Randomized Controlled Trial

We aimed to investigate high-order aberration (HOA) change between topography-guided (TG) and wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) in patients with different degrees of myopia. A non-randomized clinical trial was conducted, in which 40 eyes of 20 patients aged 20-50 years old were included. Participants received TG-LASIK in one eye and WFO-LASIK on the alternate eye. Corneal topography and HOAs including coma, trefoil, spherical aberration (SA), and contrast sensitivity (CS) were collected. Moreover, a quality of vision (QoV) questionnaire was completed by each participant. Non-parametric tests were used to infer the difference in HOAs and CS between the TG-LASIK and WFO-LASIK groups, and subgroup analyses stratified by myopia degree were performed. The high-myopia patients with TG-LASIK showed more coma and SA compared to low-myopia individuals (all 95% CI lower limits > 0), and subjects who received WFO-LASIK exhibited more SA in high-myopia status (both 95% CI lower limits > 0). The TG-LASIK group showed lower postoperative trefoil compared to the WFO-LASIK group in the high-myopia population (mean difference: -0.1267, 95% CI: -0.24 to -0.01). The TG-LASIK group yielded less surgically induced haze, better clarity at night, and better total quality scores (all p < 0.05). In conclusion, TG-LASIK might yield less postoperative trefoil in high-myopia patients and higher QoV in the general population compared to the WFO-LASIK procedure.

Comparison of refractive and visual acuity results after Contoura® Vision topography-guided LASIK planned with the Phorcides Analytic Engine to results after wavefront-optimized LASIK in eyes with oblique astigmatism.

To compare visual acuity and refractive results between topography-guided laser in situ keratomileusis (LASIK) planned with the Phorcides Analytic Engine (PAE) to results after wavefront-optimized (WFO) LASIK in subjects with preoperative oblique astigmatism in their manifest refraction. This was a retrospective chart review of clinical results from eyes treated with topography-guided LASIK planned with PAE compared to eyes treated with WFO LASIK using the same Wavelight® excimer laser system. All included subjects had preoperative oblique astigmatism. Residual refractive error and visual acuity (uncorrected and corrected) were the measures of interest, at the visit closest to 90 days postoperative. A matched data set from 100 WFO and 97 PAE eyes was extracted from clinical records. At the postoperative visit the PAE group showed lower residual refractive cylinder (p = 0.04), uncorrected distance visual acuity (UDVA) (-0.06 PAE vs. -0.02 WFO, p < 0.01) and distance corrected visual acuity (CDVA) (p < 0.01). The percentage of eyes with a mean refraction spherical equivalent (MRSE) magnitude within 0.25 D and 0.50 D of plano was statistically significantly higher in the PAE group (p = 0.04 and 0.01, respectively). A statistically significantly higher percentage of eyes in the PAE group had UDVA better than or equal to -0.10 logMAR (20/16 Snellen, 36% vs 22%, p = 0.04). More eyes gained CDVA after surgery in the PAE group (53% vs 32%, p < 0.01). There were five enhancements in the WFO group versus none in the PAE group, a statistically significant difference (p = 0.03). Visual acuity and refractive outcomes after LASIK using PAE in eyes with oblique astigmatism in their preoperative refraction were statistically significantly better than those obtained when WFO treatment was used. The number of refractive outliers and the number of retreatments were also significantly lower with PAE treatment.

Posterior Corneal Astigmatism Does Not Influence Manifest-Treated Topography-guided LASIK Outcomes

To investigate whether the magnitude of posterior corneal astigmatism (PCA) impacts refractive and visual outcomes of primary topography-guided laser in situ keratomileusis (LASIK) and to provide guidance on treating eyes with high PCA. Comparative retrospective analysis of 4,541 consecutive eyes treated with Contoura (Alcon Laboratories, Inc) on the manifest refractive astigmatism. Standard outcomes of the 1,514 eyes with the lowest PCA (first tercile; low PCA group) were compared to the 1,514 eyes with the highest PCA (last tercile; high PCA group). Pearson correlation coefficient was used to assess relationships between variables. Preoperatively, 20.9% of eyes presented with PCA of 0.50 diopters (D) or greater. The mean PCA was 0.18 ± 0.07 D in eyes with low PCA, and 0.50 ± 0.11 D in eyes with high PCA. An equivalent number of eyes achieved a cumulative postoperative unilateral uncorrected distance visual acuity of 20/20 in both the low PCA and high PCA groups (95.3% vs 94.7%; P = .4489). The efficacy index of both low and high PCA eyes was identical (0.99 ± 0.06 vs 0.99 ± 0.08; P = .3192), as was the safety index (1.00 ± 0.02 vs 1.00 ± 0.03; P = .0110). The magnitude of preoperative PCA was weakly correlated with postoperative refractive astigmatism (R = 0.1323), but not with postoperative defocus equivalent (R = -0.0414) or spherical equivalent (R = -0.0128). PCA does not negatively impact the outcomes of topography-guided LASIK targeting the manifest refraction, having identical accuracy, efficacy, and safety in eyes with both low and high PCA. There is no scientific basis to measure and consider PCA in topography-guided LASIK planning software or nomograms if the excimer laser treatment input targets the manifest refraction. [J Refract Surg. 2022;38(12):780-790.].

Effect of corneal epithelial remodeling on visual outcomes of topography-guided femtosecond LASIK.

To assess the effect of epithelial remodeling on visual outcomes over a 9 mm diameter corneal surface after topography-guided laser in situ keratomileusis (LASIK) for myopia correction using spectral-domain anterior segment optical coherence tomography (AS-OCT). Outpatient clinical practice at the Stanford University Byers Eye Institute in Palo Alto, California. Prospective nonrandomized observational study. Visual acuity, including uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), 5% and 25% contrast sensitivity CDVA, manifest refraction, and corneal epithelial thickness after topography-guided femtosecond LASIK were analyzed. Corneal epithelial thickness was mapped across 13 sections and 3 concentric zones using AS-OCT preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. 60 eyes of 30 patients with a mean age of 32.8 years (range 23 to 52 ± 7.03 years) undergoing myopic LASIK correction were assessed. In eyes with complete follow-up data (n = 30), mean preoperative UDVA was logMAR 1.48 ± 0.45 and logMAR -0.11 ± 0.08 at postoperative 12 months. Mean preoperative CDVA was logMAR -0.08 ± 0.11 and logMAR -0.13 ± 0.07 at 12 months. Linear mixed modeling demonstrated a significant correlation between improvement in UDVA and decreased superior and nasal corneal epithelial thickness and between improvement in CDVA and increased central epithelial thickness 12 months postoperatively. Improvement in UDVA and CDVA at 12 months after topography-guided femtosecond LASIK was correlated with nonuniform epithelial remodeling, including epithelial thickening in the central zone and thinning in the superior and nasal sections as measured by AS-OCT.

Visual differences in topography-guided versus wavefront-optimized LASIK in the treatment of myopia: a Meta-analysis.

To investigate the potential differences between topography-guided (TG) and wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) for the treatment of myopia. A systematic literature search was performed to determine relevant trials comparing LASIK with TG and WFO from the time of library construction to August 2020, and The PubMed, Cochrane, Web of Science, EMBASE and Chinese databases (i.e. CNKI, CBM, WAN FANG and VIP) were accessed. The data on visual acuity, refractive status and wavefront aberration were retrieved and evaluated from three to six months after surgery. STATA (version 14.0) software was used for statistical analysis. A cumulative Meta-analysis was simultaneously performed. Eleven studies with a total of 1425 eyes were incorporated. No statistically significant differences were evident between TG and WFO ablation in the proportion of eyes achieving an uncorrected distance visual acuity (UCVA) of 20/20 or better (P=0.377), gaining one line or more (P=0.05), postoperative cylinder (P=0.40), vertical coma (P=0.593) and horizontal coma (P=0.957). After TG ablation, the proportion of the patients' eyes of which postoperative refraction is within ±0.5 diopter of the target refraction was significantly higher than that undergoes WFO (P=0.003). As opposed to the WFO group, manifest refraction spherical equivalent (MRSE; P=0.000) was lower, and UCVA (P=0.005) was better in the TG group. The higher-order aberrations (HOAs; P=0.000), spherical aberration (P=0.000) and coma (P=0.000) were significantly lower in TG group. The cumulative Meta-analysis illustrated that the proportion of eyes achieving UCVA of 20/20 or better, postoperative refraction within ±0.5 diopter, and MRSE has steady between the two groups. Both TG-LASIK and WFO-LASIK are safe, effective, and predictable for correcting myopia. TG-LASIK may produce fewer aberration and is more precise than WFO-LASIK.

Large Axis Difference Between Topographic Anterior Corneal Astigmatism and Manifest Refractive Astigmatism: Can Topography-Guided LASIK Target the Manifest Axis?

To investigate whether the degree of astigmatism axis discrepancy between preoperative manifest refractive astigmatism and anterior corneal astigmatism impacts refractive and visual outcomes of primary topography-guided laser in situ keratomileusis (LASIK) targeting the refractive astigmatism, and to provide guidance on treating eyes with very large axis discrepancy. Comparative retrospective analysis of 25,396 consecutive eyes treated with topography-guided LASIK on the manifest refractive astigmatism. Standard outcomes of the 14,534 eyes with small axis discrepancy (SAD) (Δ in axis ⩽ 10°) were compared to the 2,222 eyes with very large axis discrepancy (VLAD) (Δ in axis ⩾ 45°). Pearson correlation coefficient was used to assess relationships between selected variables. The mean axis discrepancy was 4.47 ± 2.92° in SAD eyes, and 65.0 ± 13.4° in VLAD eyes. An equivalent number of eyes achieved a cumulative postoperative unilateral uncorrected distance visual acuity of 20/20 in both the SAD and VLAD groups (93.02% vs 93.42%; P = .4892). The efficacy index (0.98 ± 0.13 vs 0.98 ± 0.07; P = .3931) and the safety index (1.00 ± 0.11 vs 1.00 ± 0.03; P = .4757) were identical between groups. There was no clinically meaningful correlation between the preoperative axis discrepancy and preoperative total root mean square anterior corneal coma, postoperative refractive astigmatism, defocus equivalent, spherical equivalent, and angle of error, all with weak correlation coefficients (R = -0.02, -0.03, -0.02, 0.01, and 0.05). Large preoperative axis discrepancy (45° to 90°) between refractive astigmatism and topography-measured anterior corneal astigmatism does not negatively impact topography-guided LASIK, having identical refractive and visual outcomes compared to eyes with small (0° to 10°) discrepancy. There is no basis to exclude eyes with large axis discrepancy from topography-guided LASIK, and these eyes should be treated on the manifest refractive astigmatism. [J Refract Surg. 2021;37(10):662-673.].

Comparison of clinical outcomes of 2 platforms for topography-guided LASIK in primary eyes.

To compare differences in visual, refractive, and ablating outcomes between corneal topography-guided laser in situ keratomileusis (LASIK) by SCHWIND AMARIS and WaveLight Contoura for myopia and myopic astigmatism correction. Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Guangzhou, China. Prospective nonrandomized study. Patients treated with LASIK to correct ametropia and corneal higher-order aberrations (HOAs) with 6.5 mm of plan optical zone were recruited. In the AMARIS platform, there were 2 centration strategies: the symmetric (AA) and asymmetric (AS) offset modes. In the WaveLight platform, there was only symmetric offset (ES) mode. HOAs, contrast sensitivity, effective optical zone (EOZ), ablation depth, and ablating center were evaluated 3 months after the operation. The study included 138 eyes. At 3 months after operation, the postoperative manifest refractive spherical equivalent was 0.04 ± 0.34 diopters (D), 0.06 ± 0.25 D, and -0.09 ± 0.21 D in AS, AA, and ES groups, respectively (P = .018). The EOZs of the AS and AA groups were 5.01 mm and 4.96 mm, and both were larger than 4.88 mm in the ES group (P = .04 and .03, respectively). The ablation depth of the AS group was 103.6 μm, which were larger than 86.6 μm in the AA group and 91.2 μm in the ES group. The SCHWIND AMARIS and WaveLight EX500 corneal topography-guided LASIK achieved comparable and excellent visual and refractive outcomes. The EX500 Contoura LASIK ablated less corneal tissue because of the smaller EOZ compared with the AMARIS, with a similar plan optical zone.

Comparison of effective corneal refractive centration to the visual axis: LASIK vs SMILE, a contralateral eye digitized comparison of the postoperative result.

To define and compare the centration of the ablation effect in laser in situ keratomileusis (LASIK) with the corresponding effect in small-incision lenticule extraction (SMILE), in myopic laser vision correction to possibly explain the refractive performance differences noted between the two procedures in a contralateral eye study. Private ambulatory eye surgery unit. Prospective randomized contralateral eye study. In 22 consecutive patients (44 eyes), 1 eye was prospectively randomized to undergo myopic topography-guided LASIK treatment and the contralateral eye to undergo SMILE; digital image analysis of the achieved centration to the aimed corneal vertex was assessed for both procedures on perioperative Scheimpflug tangential curvature maps, using a proprietary digitized methodology. The radial displacement measured in micrometers in the above treated 44 eyes, between the attempted centration point on the corneal vertex vs the center of the measured effective anterior corneal curvature flattening was on average 130 ± 62 mm in the 22 eyes of LASIK group and 313 ± 144 mm in the 22 contralateral eyes of the SMILE group (P < .001). In this contralateral eye study, topography-guided myopic LASIK was found to achieve significantly better effective centration compared with myopic SMILE, in regard to digitally measured decentration of the effective refractive change achieved in the anterior corneal curvature from the corneal vertex. This may explain the previously reported superior visual outcomes in the LASIK group eyes when compared with the contralateral SMILE group eyes.

Topography-guided laser in-situ keratomileusis to treat visual distortions due to higher-order aberrations induced after ablation procedures

A 27-year-old male, with a history of bilateral Laser in situ keratomileusis (LASIK) followed by photorefractive keratectomy, presented with complaints of disturbed quality of vision, the right eye worse than the left eye. Uncorrected distance visual acuity (UDVA) was 20/20 in both eyes. Corneal topography and wavefront aberrometry revealed slightly decentered ablation and increased higher-order aberrations in the right eye, respectively. A topography-guided femtosecond-assisted LASIK was performed for the right eye successfully reducing his visual symptoms and conserving UDVA at 20/20.

&lt;p&gt;Primary Topography-Guided LASIK: A Comparative Study Comparing Treating the Manifest versus the Topographic Astigmatism&lt;/p&gt;

PurposeTo investigate if topography-guided laser in situ keratomileusis (LASIK) depending on the topographic astigmatism which is measured using the Topolyzer leads to a better refractive outcome when compared to treatment of the manifest refractive astigmatism in cases of myopic astigmatism.MethodsThis was a prospective non-masked, randomized study (block randomization) of postoperative vision and refraction of patients with myopic astigmatism that had LASIK using Contoura vision software. They were divided into three groups according to the treatment strategy, treating the manifest astigmatism in one group, the topographic astigmatism with compensation for the spherical power in the second group and treating the topographic astigmatism without changing the spherical power in the third group. It was conducted at Kasr Alainy Hospital and Dar Eloyon Hospital.ResultsThe postoperative uncorrected distant visual acuity (UDVA) in each group separately was better than the preoperative corrected distant visual acuity (CDVA) (58% (n=35) had UDVA better than 20/20 and gained 1 line or more); however, eyes treated with the topographic astigmatism without changing the spherical power showed the statistically best results (75% (n=15) had UDVA better than 20/20). The residual anterior corneal astigmatism was lower in this group (the mean 0.47 vs 0.95 and 0.59). No significant difference was noted in the residual refractive astigmatism, but it was also the least in that group.ConclusionTopography-guided LASIK is a safe and effective ablation profile for treatment of myopic astigmatism. Treating according to the topographic astigmatism shows the best outcome as regards the vision and residual astigmatism.

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.

Clinical outcomes after topography-guided LASIK: comparing results based on a new topography analysis algorithm with those based on manifest refraction.

To compare short-term refractive and visual acuity outcomes after topography-guided laser in situ keratomileusis (LASIK) planned with a new topography analysis system to those based on the manifest refraction. Four clinical sites in the United States. Double-arm, nonmasked, nonrandomized retrospective chart review. This was a retrospective study of postoperative refraction and visual acuity at least 2 months after uneventful LASIK using the Contoura Vision algorithm on the WaveLight Topolyzer VARIO laser. One arm comprised eyes treated using the manifest refraction (manifest), while the other included eyes treated with an ablation profile determined by the Phorcides Analytic Engine (analytic). Clinical results from a matched group of 317 manifest eyes and 323 analytic eyes were available for analysis. Residual refractive results, both sphere and cylinder, were similar between groups. However, significantly more eyes had 20/16 or better (-0.1 logarithm of the minimum angle of resolution) uncorrected distance visual acuity (UDVA) (62.5% analytic, 41.3% manifest) and corrected distance visual acuity (CDVA) (77.1% analytic, 51.4% manifest) in the analytic group. All eyes but 1 had a CDVA of 20/20 or better postoperatively. The number of patients with a UDVA better than their preoperative CDVA was significantly higher in the analytic group (36.5%) relative to the manifest group (23.0%). No eye in either group lost more than 1 line of CDVA; significantly more eyes in the analytic group (42.7%) gained 1 or more lines of CDVA relative to the manifest group (30.3%). Using the Phorcides Analytic Engine for topography-guided surgery planning increased the likelihood of 20/16 UDVA and CDVA relative to using the manifest refraction.

SMILE, Topography-Guided LASIK, and Wavefront-Guided LASIK: Review of Clinical Outcomes in Premarket Approval FDA Studies.

To review clinical outcomes of the U.S. Food and Drug Administration premarket approval (PMA) studies of the three recently approved refractive surgery platforms for the correction of spherocylindrical myopia. Clinical outcomes and vector analysis of astigmatism were reviewed and compared between wavefront-guided laser in situ keratomileusis (LASIK) (WFG group) (STAR S4 IR with iDesign aberrometer; Johnson & Johnson Vision Care, Inc., Santa Ana, CA), topography-guided LASIK (TOPO group) (Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX), and small incision lenticule extraction (SMILE group) (VisuMax laser; Carl Zeiss Meditec AG, Jena, Germany). The number of eyes included was 304, 249, and 334 for the SMILE, TOPO, and WFG groups, respectively. The WFG group had the highest preoperative spherical equivalent refraction (-6.21 ± 2.78 diopters [D]), followed by the SMILE (-5.39 ± 2.30 D) and TOPO (-4.61 ± 2.43 D) groups. At 6 months postoperatively, 83.7%, 88.9%, and 82.6% of eyes in the SMILE, TOPO, and WFG groups, respectively, had uncorrected distance visual acuity (UDVA) of 20/20 or better. SMILE showed slower visual recovery at early postoperative examinations, whereas the WFG group had a decrease in UDVA over time due to refractive regression. The mean refractive cylinder changed from -1.53 ± 0.70 D preoperatively to -0.22 ± 0.33 D at 6 months postoperatively in the SMILE group, -1.19 ± 1.23 to -0.19 ± 0.30 D in the TOPO group, and -1.77 ± 1.65 to -0.33 ± 0.36 D in the WFG group. With all three procedures, undercorrection of refractive cylinder was seen with increasing attempted correction. All three procedures demonstrated excellent outcomes, considering differences in attempted correction between studies. No obvious superiority of one technique over the others was found in astigmatic correction. [J Refract Surg. 2019;35(11):690-698.].

Topography-guided versus wavefront-optimized laser in situ keratomileusis for myopia: Surgical outcomes

To compare the outcomes of topography-guided and wavefront-optimized surgery in patients having laser insitu keratomileusis (LASIK) for myopia. Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, and BALGEUN-EYE21 Operation Center, Gwangju, South Korea. Prospective case study. Patients had topography-guided LASIK in 1 eye and wavefront-optimized LASIK in the contralateral eye using Contoura Vision software and the WaveLight EX500 excimer laser. Refractive and visual outcomes were analyzed 3months postoperatively. The study comprised 43 patients. In both groups, the postoperative uncorrected distance visual acuity (UDVA) was 0.0 logarithm of the minimum angle of resolution or better in 90.7% of eyes and the residual spherical equivalent (SE) refractive error was ±0.75 diopter (D) in 81.4% of eyes. The UDVA, residual SE refractive error, and astigmatism did not differ significantly between the 2 groups. There was significant induction of higher-order aberrations (HOAs) in both groups, although corneal coma and trefoil did not increase and ocular trefoil decreased significantly in the topography-guided group (P=.038). However, in the wavefront-optimized group, corneal coma and trefoil increased significantly (P<.001 and P=.046, respectively) and ocular trefoil did not change significantly. In addition, topography-guided LASIK induced significantly fewer corneal total HOAs (P<.001), coma (P<.001), and trefoil (P=.020) than wavefront-optimized LASIK. Although both topography-guided LASIK and wavefront-optimized LASIK safely and effectively achieved the predicted refractive and visual outcomes, topography-guided LASIK induced fewer HOAs and significantly decreased ocular trefoil, corneal total HOAs, and coma.

More eyes with 20/10 distance visual acuity at 12 months versus 3 months in a topography-guided excimer laser trial: Possible contributing factors

To study eyes with 20/10 uncorrected distance visual acuity (UDVA) 3months and 12months after topography-guided LASIK for myopia and myopic astigmatism, and to identify factors predictive of this excellent level of visual acuity. Nine practices in the USA. Prospective unmasked study of safety and effectiveness. The percentage of eyes with UDVA of 20/10 or better at 3months and 12months after topography-guided laser insitu keratomileusis (LASIK) with the Contoura Vision excimer laser in a U.S. Food and Drug Administration clinical trial was compared, and possible contributing factors were investigated. Preoperatively, only 1% of eyes had 20/10 corrected distance visual acuity (CDVA). Postoperatively, 7.0% of eyes had 20/10 or better UDVA at 3months, and this number increased to 16% at 12months (odds ratio, 2.48; 95% confidence interval, 1.33-4.61). The lower preoperative corneal astigmatism and postoperative refractive cylinder correlated with better postoperative UDVA and CDVA, respectively (P<.01 in all cases). The postoperative UDVA correlated with the postoperative CDVA (P<.01). The number of eyes with UDVA of 20/10 increases significantly between 3months and 12months after topography-guided LASIK and correlates with better postoperative CDVA. Eyes with lower preoperative corneal astigmatism are more likely to achieve 20/10 or better UDVA postoperatively. A significant improvement in the number of eyes with 20/10 or better from 3months to 12months after LASIK might be unique to topography-guided treatment.

Primary Topography-Guided LASIK: Refractive, Visual, and Subjective Quality of Vision Outcomes for Astigmatism ⩾2.00 Diopters.

To evaluate the outcomes of primary topography-guided laser in situ keratomileusis (LASIK) in eyes with subjective refractive astigmatism of 2.00 diopters (D) or greater. This was a prospective study in consecutive eyes with cylinder of 2.00 D or greater that had LASIK using the Alcon WaveLight EX500 excimer laser and T-CAT/Contoura software (Alcon Laboratories, Inc., Fort Worth, TX). The accuracy, efficacy, safety, cylinder vector analysis, higher order aberrations, and patients' subjective quality of vision were assessed. Eyes with naturally occurring topographic irregular astigmatism were not excluded. The mean cylinder was -2.55 D preoperatively and -0.34 D postoperatively; 81% and 95% of eyes were within ±0.50 and ±0.75 D of intended cylinder after LASIK, respectively. The correction index and index of success were 1.00 and 0.13, respectively. The efficacy and safety indexes were 0.98 and 1.04, respectively. The preoperative corneal topography irregularity index, anterior corneal higher order aberrations, and refractive astigmatism magnitude were mildly correlated to postoperative residual astigmatism. Mean ocular and corneal coma were not increased postoperatively. Patients had significant improvements after LASIK in both subjective uncorrected quality of vision and night vision disturbances compared to spectacle- and contact lens-corrected vision before LASIK. Topography-guided ablation using the Alcon WaveLight EX500 excimer laser and T-CAT/Contoura software results in excellent accuracy, efficacy, and safety, with improved postoperative subjective quality of vision and reduced night vision disturbances in virgin eyes with refractive astigmatism of 2.00 D or greater, including eyes with topographic naturally occurring irregular astigmatism. [J Refract Surg. 2019;35(2):78-86.].

Q Value Based Ablation Profile versus Topography - Guided LASIK : A Contralateral Comparative Study

Background: laser in situkeratomileusis (LASIK) has become the most widely used form of refractive surgery. The objective of this surgical technique was to modify the anterior corneal shape by ablating tissue from the stroma by means of the excimer laser after creating a hinged corneal flap. By this way, we were able to change the refractive status of the patient and provided better unaided vision. Continuous improvements in the original technique made the surgical procedure safer, more accurate and repeatable. These progressions are due to the development of novel technologies that are responsible for new surgical instrumentation, which makes the surgical procedure easier for the surgeon and better excimer laser ablation algorithms, which increase the optical quality of the ablation and thus the safety of the vision correction procedure. Aim of work: the aim of this study was to compare between Q value based ablation and topography-guided LASIK as regards safety, visual acuity, contrast sensitivity and high order aberration HOAs (spherical, coma and trefoil). Patients and methods: this study was conducted on 60 eyes of 30 patients, thirty eyes of them underwent topography guided LASIK and the other 30 underwent Q value based ablation. Preoperative CDVA (corrected distant visual acuity) was done. Postoperative UDVA and CDVA were measured. Postoperative high order aberrations were measured 3 months postoperatively. Results: our results showed that there was no statistically significant difference between both groups as regards UDVA, spherical equivalent, high order aberrations and Strehl ratio point spread function. Conclusion: topographic guided ablation and Q value based groups provided essentially equivalent outcomes after myopic LASIK, with statistically insignificant difference between both profiles, although both laser profiles have been found to be effective, safe and predictable.

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

To compare the outcomes of topography-guided and wavefront-optimized treatment in patients having laser in situ keratomileusis (LASIK) for myopia. Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India. Prospective contralateral-eye case study. 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 6months postoperatively. 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 61.57μm±16.23 [SD]) than in the wavefront-optimized group (mean 79.71±14.81μm)(P<.001). 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. None of the authors has a financial or proprietary interest in any material or method mentioned.

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

To assess the efficacy, predictability, safety, and quality-of-life effects of topography-guided laser in situ keratomileusis (LASIK) for the correction of myopia with astigmatism using the EC-5000 CXII excimer laser equipped with a customized aspheric treatment zone algorithm. Ophthalmology clinics in the United States and Mexico. In a multicenter United States Food and Drug Administration study of topography-guided LASIK, 4 centers enrolled 135 eyes with a spherical manifest refraction error ranging from -0.50 to -7.00 diopters (D) and astigmatism ranging from 0.50 to 4.00 D. All eyes were targeted for emmetropia. Refractive outcomes, higher-order aberrations (HOAs), and contrast sensitivity were analyzed preoperatively and postoperatively. Patient satisfaction was assessed using 2 questionnaires. Six months postoperatively, the mean manifest refraction spherical equivalent in all eyes was -0.09 D +/- 0.31 (SD); of the 131 eyes, 116 (88.55%) had an uncorrected visual acuity of 20/20 or better and 122 (93.13%) had an MRSE within +/-0.50 D. The best spectacle-corrected visual acuity (BSCVA) increased by 2 or more lines in 21 (16.03%) of 131 eyes; no eye lost 2 lines or more of BSCVA. The total ocular HOA increased by 0.04 microm. Patients reported significantly fewer night driving and glare/halo symptoms postoperatively than preoperatively. Use of a customized aspherical treatment zone in eyes with myopia and astigmatism was safe, effective, and predictable and reduced symptoms associated with night driving, glare, and halos.