Wavefront-optimized Research Articles

Low Contrast Acuity Outcomes After SMILE and LASIK.

To compare early visual quality of small incision lenticule extraction (SMILE) versus laser in situ keratomileusis (LASIK) in terms of low contrast acuity. A secondary analysis was performed using a harmonized dataset derived from two completed prospective cohort studies on active-duty military service members undergoing either SMILE (n = 37), wavefront-guided (WFG) LASIK (n = 51), or wavefront-optimized (WFO) LASIK (n = 56). Night vision and photopic and mesopic low contrast visual acuity (LCVA) up to 3 months postoperatively were compared between groups. Compared to SMILE-treated eyes, WFG LASIK-treated eyes had significantly better night vision and photopic LCVA at 1 month postoperatively (beta = -0.039, P = .016; beta = -0.043, P = .007, respectively). WFO LASIK-treated eyes had significantly better photopic LCVA at 1 month postoperatively (beta = -0.039, P = .012) but had worse mesopic LCVA at 3 months postoperatively (beta = 0.033, P = .015) versus SMILE-treated eyes. SMILE and LASIK, on either a WFG or WFO laser platform, yielded excellent outcomes, but LCVA seemed to recover quicker following LASIK compared to SMILE. [J Refract Surg. 2024;40(9):e667-e671.].

Comparison of Outcomes after Wavefront-optimized and Topography-guided Transepithelial Photorefractive Keratectomy.

To evaluate the outcomes of wavefront-optimized (WFO) and topography-guided (TG) transepithelial photorefractive keratectomy (transPRK) in the treatment of myopia and myopic astigmatism. Patients who underwent transPRK using the WaveLight EX500 excimer laser for the correction of myopia and myopic astigmatism between January 2022 and March 2023 were divided into groups of WFO transPRK (77 eyes of 36 patients) or TG transPRK (63 eyes of 31 patients) in this retrospective, observational cohort study. The preoperative and postoperative 3-month refractive and visual outcomes of the two groups were analyzed. In both groups, the uncorrected distance visual acuity was 0.0 logarithm of the minimum angle of resolution or better in 95% of eyes 3 months postoperatively, and the mean manifest refraction spherical equivalent was within ±1.0 diopter in 90% of eyes. No significant differences were observed between the groups in terms of the uncorrected distance visual acuity or astigmatism. A significant induction of higher order aberrations (HOAs) was observed in both groups. However, the induction of total corneal HOAs (p = 0.014) and spherical aberrations (p < 0.001) was significantly lower in the TG group than that in the WFO group. WFO and TG transPRK effectively improved the visual and refractive outcomes; however, the induction of total corneal HOAs and spherical aberration was lesser following the TG ablation.

Retrospective Study Comparing Topography-Guided and Wavefront-Optimized LASIK Procedures in a Single Center.

To compare visual outcomes of eyes that had laser refractive surgery with the Contoura Phorcides treatment plan and eyes that had laser refractive surgery with the wavefront-optimized treatment plan using the same laser. Retrospective chart review of clinical outcomes of eyes that had either Contoura with Phorcides (CP) or wavefront-optimized (WFO) corneal refractive procedures using the Wavelight EX500 (Alcon Vision, LLC). Data were collected and compared for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, change in postoperative UDVA compared to preoperative CDVA, and change in postoperative CDVA compared to preoperative CDVA. Total eyes included were 348, with 227 in the CP Group and 121 in the WFO Group. Post-operatively, there was a significantly higher percentage of eyes in the CP Group that were 20/16 or better compared to the WFO Group (57%, 129 eyes, and 17%, 21 eyes, respectively; p < 0.001). The percentage of eyes that gained 1 or more Snellen lines of UDVA compared to preoperative CDVA was higher in the CP Group (47%; 107 eyes) compared to the WFO Group (12%; 14 eyes), which was statistically significant (p < 0.001). Differences in refraction were statistically significant. Topography-guided and wavefront-optimized treatment profiles both provided excellent refractive results. A higher percentage of eyes that were treated using Contoura with Phorcides achieved 20/16 or better unaided distance vision compared to eyes receiving a wavefront-optimized treatment plan.

Comparison of Higher Order Aberrations between Wavefront Optimized Photorefractive Keratectomy and Laser in situ Keratomileusis in Myopic Patients.

To compare the higher order aberrations (HOA) between wavefront optimized (WFO) laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in myopic patients. Quasi-experimental study. Place and Duration of the Study: Armed Forces Institute of Ophthalmology, Rawalpindi, Pakistan, from December 2021 to December 2022. Forty-four patients underwent wavefront optimized PRK and fifty-seven patients underwent wavefront optimized LASIK. All variables were recorded before the procedure and at 1, 3, 6, and 12 months postoperatively and included uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), root mean square (RMS) of HOAs, spherical aberration (SA), and coma aberration (CA). A total of 101 eyes of 51 patients were considered in the final analysis. Patients were divided into two groups. Group A comprised of 44 (43.6%) eyes of 22 patients who underwent PRK while group B comprised of 57 (56.4%) eyes of 29 patients who underwent LASIK. UCVA significantly improved postoperatively at 3 and 6 months in both PRK and LASIK groups (p<0.001 for both groups). In this study, the increase in root mean square (RMS) of higher order aberrations from baseline value was 77% after PRK and 28% after LASIK, similar ratio was observed in spherical aberration (SA). The trend of rise in Coma aberrations was more in LASIK group 66.49%as compared to 46.2% in PRK group. Both Wavefront Optimized PRK and LASIK are safe and have elicited comparable results of post-procedure visual recovery. There was a marked increase in RMS of HOAs in PRK group as compared to WFO LASIK group while coma aberration increased more in LASIK as compared to PRK postoperatively. LASIK, PRK, RMSh, HOAs, Spherical aberration, Coma, Myopia.

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.

Q-value customized versus wavefront-optimized ablation in femtosecond laser-assisted LASIK for myopia and myopic astigmatism: a prospective contralateral comparative study

BackgroundCorneal refractive surgery for myopia results in an oblate shift with increased postoperative aberrations inversely affecting the quality of vision. Aspheric ablation profiles have been introduced to minimize such a problem. The aim of this study was to compare changes in corneal asphericity, central and mid-peripheral pachymetry between the Q-value customized and the wavefront-optimized (WFO) ablation profiles. MethodsA prospective, comparative non-randomized fellow eye study was conducted. Eighty eyes of 40 eligible patients underwent femtosecond laser-assisted laser in situ keratomileusis for myopia and myopic astigmatism. In each patient, the more myopic eye was included in the custom-Q ablation experimental group and the other less myopic eye was included in the WFO control group. For the custom-Q group, the target asphericity was set to the preoperative Q-value. Corneal asphericity, central and mid-peripheral pachymetric changes and the root mean square of corneal higher-order aberrations (RMSh) were assessed 6 months following surgery. Visual and refractive outcomes were also evaluated in both platforms 6 months postoperatively.ResultsThe mean preoperative refractive spherical equivalent was significantly more myopic in the custom-Q group than in the WFO group (P = 0.001). The mean Q-value changed from − 0.2 ± 0.1 to 0.6 ± 0.7 and from − 0.2 ± 0.1 to 0.4 ± 0.5 in the custom-Q and WFO groups, respectively. The oblate shift in corneal asphericity was not significantly different between both treatment groups (P = 0.094). The mean ablation depth at the pupillary center was significantly greater in the custom-Q group (P = 0.011), while there was no significant difference at the mid-peripheral pachymetry (P = 0.256). The RMSh significantly increased in both treatment profiles (P < 0.001) with no significant difference between the two groups (P = 0.06). The uncorrected distance visual acuity (UDVA) and the manifest refraction spherical equivalents (MRSE) significantly improved in both treatment groups (P < 0.001).ConclusionsThe custom-Q treatment profile with target asphericity set at the preoperative Q-value achieved comparable outcomes vs. the WFO profile in terms of postoperative corneal asphericity and mid-peripheral pachymetry despite the greater amount of ablation, the smaller optical zone, and the resulting increase in postoperative corneal flattening in the custom-Q group.Trial registration (Clinicaltrials.gov): NCT04738903, 4 February 2021- Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04738903

Comparison Between the Wavefront-Optimized and Custom-Q Aspheric Ablation Profiles in Myopic Eyes With Two Different Q-targets: A Contralateral Eye Study.

To compare two aspheric ablation profiles in myopic refractive surgery using different asphericity targets. Patients underwent laser in situ keratomileusis (LASIK) with the WaveLight EX500 laser platform (Alcon, WaveLight Laser Technologie). Asymmetric surgery was performed, programming the wavefront-optimized (WFO) ablation profile in one eye and the custom-Q (CQ) profile in the contralateral eye. The patients were divided into two groups following a systematic randomization method. The Q-target programmed for the preoperative Q group was equal to the preoperative asphericity of the CQ profile, and for the -0.6 Q-target group, the Q-target was set to -0.6. The study included 100 patients (200 eyes). Both groups had comparable safety and efficacy indexes greater than 1. A similar oblate shift in postoperative asphericity was seen in both groups regardless of the ablation profile and programmed Q-target. Asphericity was 0.33 ± 0.34 and 0.35 ± 0.29 (P = .18) in the preoperative Q group and 0.26 ± 0.28 and 0.26 ± 0.27 (P = .89) in the -0.6 Q-target group for WFO and CQ, respectively. A lower spherical aberration was found with CQ compared to WFO when the Q-target was set to -0.6: 0.211 ± 0.121 versus 0.144 ± 0.114 (P < .01). However, no statistically significant differences were found when the preoperative Q-target was used. WFO and CQ treatments are similar in terms of refractive and visual outcomes. CQ offers greater control over the increase in positive spherical aberration after myopic refractive surgery, but it does not represent an advantage over WFO in the oblate shift in postoperative asphericity regardless of the Q-target programmed. [J Refract Surg. 2022;38(11):698-707.].

Comparison of Corneal Optical Quality After SMILE, Wavefront-Optimized LASIK and Topography-Guided LASIK for Myopia and Myopic Astigmatism.

PurposeTo compare visual outcomes and corneal optical quality after small incision lenticule extraction (SMILE), wavefront-optimized (WFO) FS-LASIK, and topography-guided customized ablation treatment (TCAT) FS-LASIK for myopia.MethodsThis prospective case-series study included 283 eyes of 283 myopic patients who underwent SMILE or FS-LASIK. There were 102, 100, and 81 eyes in the SMILE group, WFO group and TCAT group, respectively. The tomography system (Sirius) was used to measure corneal aberrations and optical quality.ResultsAt postoperative 1 and 6 months, there were no significant differences in uncorrected distance visual acuity and corrected distance visual acuity among the three groups (P > 0.05). Postoperative manifest refractive spherical equivalent was similar among the groups (P > 0.05). There was statistically significant difference in cylinder at 1 month among the three groups, with the highest mean value in TCAT group (P < 0.05). The corneal optical path difference, root mean square of corneal astigmatism and strehl ratio were the most superior in the TCAT group at postoperative 1 and 6 months (P < 0.05).ConclusionSMILE, WFO FS-LASIK, and TCAT FS-LASIK provided similar visual results. The corneal visual quality after TCAT FS-LASIK was the best.

A Comparison between Wavefront-Optimized and Wavefront-Guided Photorefractive Keratectomy in Patients with Moderate-to-High Astigmatism: A Randomized Clinical Trial.

Purpose:To compare clinical outcomes of wavefront-optimized (WFO) and wavefront-guided (WFG) photorefractive keratectomy (PRK) in patients with moderate-to-high astigmatism.Methods:Patients with corneal cylinder above 2 diopters and myopic spherical equivalent were randomized into WFO or WFG PRK. Visual acuity (VA), refraction, contrast sensitivity, higher-order aberrations (HOAs), and astigmatic vector differences were documented and compared for 6 months after surgery.Results:The total number of 362 eyes from 181 patients was analyzed. The amount of total aberration was reduced 2.7 root mean square (RMS) and 2.9 RMS in the WFO and WFG groups, respectively (P < 0.001 in each group and between the groups). HOAs including coma, trefoil, and spherical aberrations increased in both the groups (P < 0.001) but were significantly more in the WFO group (P < 0.001). The increased spherical aberration was similar in both the groups (P = 0.12). Surgically induced astigmatism was not significantly different between the groups (P = 0.20). The magnitude of error was significantly higher in the WFO group (P < 0.001), but the absolute angle of error and the arithmetic angle of error were not significantly different between the groups (P = 0.20 and P = 0.30, respectively).Conclusion:WFO and WFG platforms of PRK appear comparable in terms of VA, refractive correction, and total aberration. Yet, HOAs may increase especially after WFO PRK.

Functional optical zone after wavefront-optimized versus wavefront-guided laser in situ keratomileusis.

Many studies have used functional optical zone (FOZ) as a measure to compare different refractive laser treatment modalities. However, to our knowledge, no study has compared wavefront- optimized (WFO) and wavefront-guided (WFG) laser in situ keratomileusis (LASIK) using FOZ. We compared the FOZ after WFO versus WFG LASIK in patients with myopia and myopic astigmatism. In this prospective comparative study, we included 100 myopic eyes of 50 patients with or without astigmatism. They were divided into two groups according to the platform used: WFO or WFG femtosecond LASIK. Using Holladay's equivalent keratometry reading (EKR) report of Pentacam HR, FOZ was defined as a zone centered on the pupil center with a standard deviation (SD) of 0.5 D, around the mean EKR. The differences in FOZ between the two platforms were analyzed at 3 months postoperatively. Visual acuity, refractive error, corneal asphericity (Q-value), and root mean square of higher-order aberrations (RMS for HOAs) were evaluated and compared. The mean (SD) of patient age was 26.64 (5.67) years. The preoperative characteristics of the two groups were comparable (all P > 0.05). The intended optical zone (IOZ) was 6 mm in both groups. The mean laser ablation depth was significantly greater in the WFG group (18 µm per D) than in the WFO group (16 µm per D) (P = 0.035). At 3 months postoperatively, the mean (SD) of FOZ diameter was 4.32 (0.94) mm (71.99% [15.68%] of intended optical zone) in the WFO group and 4.16 (1.13) mm (69.33% [18.78%] of intended optical zone) in the WFG group, with no significant difference between the two groups (P = 0.622). The change in corneal asphericity was greater in the WFG group than in the WFO group (P = 0.034). Postoperative mean corrected and uncorrected distance visual acuity, manifest refraction, and RMS for HOAs showed no significant difference between the two groups (all P > 0.05). We found that WFG LASIK resulted in greater ablation depth and change in corneal asphericity than WFO LASIK at 3 months postoperatively. However, there was no significant difference in FOZ diameter, refractive error, and RMS for HOAs between the two groups. Further research is needed to confirm these findings.

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.

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

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. 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. 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. 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.].

Custom-Q versus Wavefront Optimized Photorefractive Keratectomy for Myopia with or without Astigmatism correction

Purpose:To compare the results between photorefractive keratectomy (PRK) with Custom-Q or with Wavefront-optimized (WFO) profiles in terms of asphericity and spherical aberrations, 6 months post-operative. Setting:Tertiary referral center (Centro Hospitalar e Universitario da Universidade de Coimbra, Coimbra, Portugal). Patients and Methods: Fifty-nine eyes (43 patients) were enrolled on this retrospective case series, including patients with myopia and/or astigmatism, submitted to refractive surgery with PRK (Allegretto WAVE Eye-Q Excimer Laser System, Alcon), in a Custom-Q ablation (38 eyes) or Wavefront-optimized procedure (21 eyes). We included patients with a minimum follow-up of 6 months; age over 21 years; stable refractive error for 2 years; spherical equivalent (SE) inferior to 5.50 diopters (D); percentage of altered tissue under 40% and expected final corneal curvature above 35 D. Eyes with other ophthalmological pathologies were excluded. Baseline and post-operative asphericity and optical aberrations were evaluated with Pentacam (Oculus Optikgerate, Wetzlar, Germany). Results: The demographic and preoperative refractive data was similar between groups (all p≥0.05). Post-operative spherical equivalent in the Custom-Q and Wavefront-optimized groups was within 0.50D in 100% and 78.90% of eyes, respectively and within 0.25D in 97.06% and 73.70% of eyes, respectively. Variation of Q-value was 0.62±0.34. (range -0.07-1.24) for Custom Q group, and 0.65±0.39 (range -0.05-1.40) in the Wavefront-optimized group (p=0.82). In a multivariate linear regression model, variation of Q-value was not influenced by the ablation profile (B=0.04, p=0.49, 95%CI [-0.08,0.17]). SE was a strong predictor (B=-0.30, p<0.01, 95%CI[-0.39,-0.21]). There was a significant increase in RMS higher-order aberrations (p<0.01for both groups) and no difference between groups (p=0.53). Discussion and Conclusion: In our sample,Custom-Q ablation was not significantly different from Wavefront optimized ablation regarding post-operative asphericity. Although the increase in higher-order aberrations, both techniques were effective and safe for myopic and/or astigmatic correction up to -5.50D SE.

Comparison of Percent Tissue altered in Topography Guided and Wavefront Optimized Laser-assisted in situ Keratomileusis using Zeiss MEL 80 Excimer Laser.

Laser-assisted in situ Keratomileusis (LASIK) is the most commonly performed refractive surgical procedure. The amount of tissue ablated in LASIK affects the safety and long-term outcome. The objective of this study was to compare the percent tissue altered (PTA) in topography guided (TG) and wavefront optimized (WFO) LASIK using Zeiss MEL 80 excimer laser. This retrospective observational study was conducted at a tertiary eye center. Patients with moderate myopia who underwent LASIK between June 2016 and January 2019 were divided into two groups (Group I: TG LASIK, 69 eyes; Group II: WFO LASIK, 70 eyes). The groups were compared for preoperative parameters [spherical equivalent (SE), keratometry and pachymetry], intraoperative parameters [ablation depth (AD), PTA and residual stromal bed thickness (RSBT)] and postoperative parameters (vision, SE). Among preoperative parameters, SE and keratometry were similar while thinnest pachymetry was significantly less in group I. Among the intraoperative parameters, PTA (P < 0.01) and AD (P < 0.01) were significantly less in group I while RSBT (P = 0.54) was not significantly different. Postoperatively at 6 months, 92.75% (64) eyes in group I and 90% (63) eyes in group II had visual acuity of 6/6 or better (P = 0.57). 98.55% (68) and 97.14% (68) eyes in group I and group II respectively had SE refraction within ± 0.5 dioptres. TG LASIK induces less tissue alteration for given refractive error with similar visual outcome as compared to WFO LASIK which makes TG apparently safer and is the preferred technique for borderline thin corneas.

From lasik to smile: Time to change laser refractive surgery

Purpose: To illustrate the advantages and limitations of Small Incision Lenticule Extraction (SMILE) over Laser Assisted Intrastromal Keratomileusis (LASIK) in the correction of myopia and myopic astigmatism. Materials and methods: The two procedures are analysed and compared for the technical aspects. While LASIK directly depends on the laser efficacy to get the refractive change, SMILE only depends on the computer ability to design the refractive lenticule. The loss in precision taking place in the peripheral cornea with LASIK is not possible with SMILE. Tissue consumption and postoperative dry eye are also lower with SMILE. Procedure abortion has less consequences with SMILE. From a clinical point of view, refractive and visual results with SMILE are similar as those of Wavefront Optimized and Wavefront Guided LASIK, but re-operations are easier after LASIK than after SMILE. Conclusion: When indicated, SMILE is better than LASIK from a technical and procedural standpoint and is equal to Wavefront Lasik as for the obtained results. LASIK is still more versatile and it is better for re-operations.

Analysis of I-Trace high-order aberrations induced by wavefront-optimized ablation profiles

Aim This work aimed to analyze the ocular aberrations induced by wavefront-optimized (WFO) ablation profiles using I-Trace aberrometer (ray tracing).Settings and design This is a prospective noncomparative nonrandomized clinical study that was carried out at Rooya Eye Center, Alexandria, Egypt.Patients and methods The study included 20 eyes of 10 cases that underwent laser in situ keratomileusis with WFO ablation profile. Cases were followed up at 1 and 3 months after surgery to analyze the ocular aberrations done using I-Trace Visual Functional Analyzer (ray tracing technology).Results The mean preoperative total high-order aberration was changed from 0.33±0.2 to 0.38±0.21 after 1 month (P=0.107) and became 0.35±0.15 at 3 months (P=0.265), which was statistically insignificant, with an increase of 6.074%. The mean preoperative coma was 0.27±0.17 and changed to 0.29±0.2 after 1 month (P=0.345) and became 0.32±0.22 at 3 months (P=0.107), which was statistically insignificant, with an increase of 17.6%. The mean increase in spherical aberrations was from 0.086±0.06 preoperatively to 0.18±0.15 after 1 month (P=0.018) and to 0.19±0.24 at 3 months (P=0.036), which was statistically significant, with an increase of 119.4%. The secondary astigmatism mean preoperative value was 0.06095±0.0439 and increased to 0.0787±0.0535 after 1 month (P=0.103) and became 0.1059±0.0592 at 3 months (P=0.098), which was statistically insignificant, with an increase of 73.7%. The trefoil preoperative mean was 0.18±0.13 and changed to 0.16±0.09 after 1 month (P=0.125) and became 0.15±0.07 at 3 months (P=0.251), which was statistically insignificant, with a decrease of −13.7%.Conclusion There was no significant total high-order aberrations increase after WFO ablation profile for low to moderate myopia.

From lasik to smile: Time to change laser refractive surgery

Purpose: To illustrate the advantages and limitations of Small Incision Lenticule Extraction (SMILE) over Laser Assisted Intrastromal Keratomileusis (LASIK) in the correction of myopia and myopic astigmatism. Materials and methods: The two procedures are analysed and compared for the technical aspects. While LASIK directly depends on the laser efficacy to get the refractive change, SMILE only depends on the computer ability to design the refractive lenticule. The loss in precision taking place in the peripheral cornea with LASIK is not possible with SMILE. Tissue consumption and postoperative dry eye are also lower with SMILE. Procedure abortion has less consequences with SMILE. From a clinical point of view, refractive and visual results with SMILE are similar as those of Wavefront Optimized and Wavefront Guided LASIK, but re-operations are easier after LASIK than after SMILE. Conclusion: When indicated, SMILE is better than LASIK from a technical and procedural standpoint and is equal to Wavefront Lasik as for the obtained results. LASIK is still more versatile and it is better for re-operations.

Quality of life and satisfaction among physicians after wavefront-optimized vs topography-guided laser vision correction.

To assess satisfaction, quality of life, occupational impact, and clinical outcomes of physicians who have undergone laser vision correction (LVC) using either wavefront-optimized (WFO) or topography-guided (TG) excimer laser ablation profile with femtosecond laser flap creation. Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA. Retrospective survey study. A 12-question survey was sent to all physicians who underwent laser in situ keratomileusis or photorefractive keratectomy at the Cole Eye Institute between 2011 and 2018 on the WaveLight Allegretto Wave Eye-Q Laser (Alcon Laboratories, Inc.). Visual outcomes were obtained from patient charts. Two hundred thirty-five physicians (454 eyes) met the study's inclusion criteria, including 181 physicians (353 eyes) who underwent WFO LVC and 54 physicians (101 eyes) who underwent TG LVC. One hundred seventeen physicians (49.8%) responded to the survey and reported an overall satisfaction rate of 98.3% among all physicians receiving LVC with 96.6% reporting they would have the procedure again. Visual outcomes showed a high level of surgical predictability, efficacy, and safety among WFO and TG eyes, with a higher percentage of eyes that received TG ablation achieving 20/10 vision (22% vs 4%, P < .0001) and 20/15 vision (87% vs 69%, P < .01) when compared with WFO eyes. Physicians who had undergone LVC with either WFO or TG excimer laser ablation reported high satisfaction and quality-of-life improvements. Both groups achieved excellent visual outcomes, with a higher percentage of TG eyes achieving 20/10 and 20/15 vision.

Comparison of outcomes after topography-modified refraction versus wavefront-optimized versus manifest topography-guided LASIK

BackgroundTo compare the outcomes of myopia and myopic astigmatism corrected with topography-modified refraction laser in situ keratomileusis (TMR-LASIK), wavefront-optimized (WFO) LASIK, and topography-guided (TG) LASIK with a correction target based on the manifest refraction (manifest TG-LASIK).MethodsThis observational, retrospective cohort study included patients who underwent LASIK using the WaveLight® EX500 excimer laser to correct myopia and myopic astigmatism between August 2016 and July 2017. Patients who underwent TMR-LASIK (85 patients), WFO-LASIK (70 patients), or manifest TG-LASIK (40 patients) were enrolled, and only one eye from each patient was analyzed. All participants underwent measurement of the uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BCVA), manifest refraction, vector analysis of astigmatic change, corneal topography, and corneal wavefront analysis at baseline and at every posttreatment visit.ResultsThree months postoperatively, a UDVA of 0.0 logMAR or better and manifest refraction spherical equivalent (MRSE) within ±0.5 diopters (D) did not differ across the TMR-, WFO-, and manifest TG-LASIK groups. However, the residual cylinder in the TMR group was significantly larger than that in the WFO and manifest TG groups. The magnitude of error in the TMR group measured using astigmatism vector analysis was significantly higher than that in the WFO and manifest TG groups.ConclusionsAlthough these three LASIK platforms achieved the predicted surgical outcomes, TMR-LASIK overcorrected astigmatism and showed a higher residual postoperative astigmatism compared with WFO- and manifest TG-LASIK.