Recent advances in wavefront-guided LASIK

Clinical outcomes after topography-guided FS-LASIK for myopia with nonastigmatic eyes

BACKGROUND

To analyze the clinical outcomes after topography-guided femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) with Phorcides Analytic Engine (PAE) algorithm or Custom-Q FS-LASIK for myopia with nonastigmatic eyes.

METHODS

In this retrospective study, a total of 90 eyes with myopia without manifest astigmatism (82 patients) were included. All surgeries were performed by topography-guided FS-LASIK planned with a PAE algorithm (42 eyes) or Custom-Q system (48 eyes). Refractive, visual outcomes and corneal aberrations were compared between the two groups.

RESULTS

At 6 months postoperatively, the postoperative uncorrected distance visual acuity (UDVA) was 20/20 or better in 42 eyes (100%) in the PAE compared with 44 eyes (92%) in Custom-Q (P = .120). The postoperative UDVA of 20/16 or better was measured in 92% of eyes in the PAE group and 81% of eyes in the Custom Q group (P = .320). Postoperative corrected distance visual acuity, manifest refractive spherical equivalent and refractive astigmatism were similar between the two groups (P > .05). The postoperative optical path difference (OPD) and Strehl ratio (SR) were significantly better in the PAE group compared with the Custom Q group.

CONCLUSIONS

Topography-guided FS-LASIK with PAE algorithm or Custom Q demonstrated similar refractive efficacy and predictability. PAE for the patients with zero manifest astigmatism demonstrated better results in correcting corneal aberrations.

BCLA CLEAR Presbyopia: Management with corneal techniques

Corneal techniques for enhancing near and intermediate vision to correct presbyopia include surgical and contact lens treatment modalities. Broad approaches used independently or in combination include correcting one eye for distant and the other for near or intermediate vision, (termed monovision or mini-monovision depending on the degree of anisometropia) and/or extending the eye's depth of focus [1]. This report reviews the evidence for the treatment profile, safety, and efficacy of the current range of corneal techniques for managing presbyopia. The visual needs and expectations of the patient, their ocular characteristics, and prior history of surgery are critical considerations for patient selection and preoperative evaluation. Contraindications to refractive surgery include unstable refraction, corneal abnormalities, inadequate corneal thickness for the proposed ablation depth, ocular and systemic co-morbidities, uncontrolled mental health issues and unrealistic patient expectations. Laser refractive options for monovision include surface/stromal ablation techniques and keratorefractive lenticule extraction. Alteration of spherical aberration and multifocal ablation profiles are the primary means for increasing ocular depth of focus, using surface and non-surface laser refractive techniques. Corneal inlays use either small aperture optics to increase depth of field or modify the anterior corneal curvature to induce corneal multifocality. In presbyopia correction by conductive keratoplasty, radiofrequency energy is applied to the mid-peripheral corneal stroma, leading to mid-peripheral corneal shrinkage and central corneal steepening. Hyperopic orthokeratology lens fitting can induce spherical aberration and correct some level of presbyopia. Postoperative management, and consideration of potential complications, varies according to technique applied and the time to restore corneal stability, but a minimum of 3 months of follow-up is recommended after corneal refractive procedures. Ongoing follow-up is important in orthokeratology and longer-term follow-up may be required in the event of late complications following corneal inlay surgery.

Comparison of clinical outcomes of a corneal wavefront- and topography-guided platforms for laser in situ keratomileusis on virgin eyes: an expanded cohort study

PURPOSE

To compare the clinical outcomes of myopiacorrected with corneal-wavefront-guided (CWG) laser in situ keratomileusis (LASIK) with AMARIS 1050S (SCHWIND eye-tech-solutions GmbH & Co. KG) and corneal-topography-guided (CTG) LASIK with WaveLight EX500 (Alcon Laboratories, Fort Worth, TX).

METHODS

In this prospective, pseudo-randomized expanded cohort study, a total of 266 patients were subjected to binocular LASIK surgery, either with WaveLight EX500 (WaveLight group) or Amaris 1050S (AMARIS group) platforms. Data related to right eyes were selected for analysis. Corneal higher-order aberration (HOA) was selected as the primary endpoint; while visual acuity and refraction were the secondary endpoints. All the endpoints were assessed at 3 months postoperatively.

RESULTS

There were 134 eyes in the AMARIS group and 132 eyes in the WaveLight group. After 3 months of postoperative follow-up, spherical and coma aberrations were significantly lower (P < 0.05) in the WaveLight group (spherical aberration: - 0.104 ± 0.199 µm; coma aberration: - 0.117 ± 0.202 µm) in comparison with the AMARIS group (spherical aberrations: 0.254 ± 0.146 µm; coma aberrations: 0.316 ± 0.297 µm). In the AMARIS group, 96.3% of the eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 while in the WaveLight group, 96.2% of the eyes achieved an UDVA of 20/20. Furthermore, the mean postoperative manifest refraction spherical equivalent (MRSE) was - 0.02 ± 0.28 in the AMARIS group and - 0.05 ± 0.21 in the WaveLight group (P = 0.34).

CONCLUSIONS

Both WaveLight EX500 and Amaris 1050S LASIK showed excellent refractive and visual outcomes. In addition, the WaveLight group showed minimal spherical and coma aberrations when compared to the AMARIS group.

The Influence of Accommodative Demand on Ocular Aberrations: A Study of Zernike Coefficients Repeatability and Variability

PURPOSE

To evaluate the repeatability of the Zernike coefficients in healthy eyes when monocular accommodation was stimulated at different vergences demands.

METHODS

A total of 36 right eyes from healthy volunteers were prospectively and consecutively recruited for this study. Wavefront aberrometry was conducted to objectively characterize the ocular optical quality during accommodation, from the individual's far point to a 5 D accommodation demand in steps of 0.5 D. The repeatability of Zernike coefficients up to the fourth order was assessed by calculating the within-eye repeatability (Sw), the coefficient of repeatability (CR), the coefficient of variation (CV), and the intraclass correlation coefficient (ICC) as an indicator of measurement reliability.

RESULTS

Correlation among repeated measurements showed high reliability (ICC > 0.513) for all parameters measured except some fourth-order Zernike coefficients, C(4, -4) (ICC < 0.766), C(4, -2) (ICC < 0.875), C(4, 2) (ICC < 0.778) and C(4, 4) (ICC < 0.811). Greater repeatability and less variability were obtained for high-order Zernike coefficients (CR < 0.154), although an increase in CR in the coefficients analyzed was observed with increasing accommodative demand. No clear trend was evident in CV; however, it was observed that the low-order Zernike coefficients exhibit lower CV (CV < 1.93) compared to the high-order Zernike coefficients (CV > 0).

CONCLUSIONS

The reliability of Zernike coefficients up to the fourth order in healthy young individuals demonstrated a strong consistency in measuring terms up to the fourth order, with more variability observed for high-order terms. The Zernike coefficients up to the third order exhibited the highest level of repeatability.

Optimization of Ray-Tracing-Guided LASIK Outcomes: A Prospective Comparative Study of ZZ InnovEyes Strategy versus Automated Strategy

Purpose

To evaluate the effectiveness of Zhang and Zheng's InnovEyes (ZZ InnovEyes) strategy for optimizing outcomes of ray-tracing-guided laser in situ keratomileusis (LASIK) compared to the standard automated strategy.

Methods

A total of 38 patients (71 eyes) undergoing therapeutic refractive surgery at Hangzhou MSK Eye Hospital were randomly assigned to the ZZ InnovEyes and automated groups using double-masked randomization. The study assessed visual acuity, refractive outcomes, and higher-order aberrations preoperatively and at 1-day, 2-week, 1-month, and 3-month follow-ups. Statistical analysis was done with Microsoft Excel and SPSS 19.0.

Results

The exposure and control groups comprised 36 and 35 eyes, respectively. The ZZ InnovEyes group demonstrated significant advantages in manifest refraction spherical equivalent (MRSE) correction compared to the automated approach group (0.13 ± 0.30 D vs 0.62 ± 0.40 D, p < 0.001), achieving 97.22% uncorrected distance visual acuity (UDVA) of 20/16 or better compared to 85.71% in the automated group at the 3-month follow-up (p = 0.08), and achieving 50.00% UDVA of 20/12.5 or better compared to 28.57% in the automated group at the 3-month follow-up (p = 0.06). Loss lines from preoperative corrected distance visual acuity to postoperative UDVA were lower in the ZZ InnovEyes group (0.00%) than the automated group (8.57%; p = 0.07). Both groups exhibited similar astigmatism corrections and higher-order aberrations.

Conclusion

The ZZ InnovEyes strategy, which incorporates manifest and wavefront refraction for ray-tracing-guided LASIK, demonstrated superior MRSE correction and potential advantages in visual acuity outcomes compared to the standard automated strategy. This study highlights the need for ongoing optimization and research in refractive surgery.

Clinical Trial Registration Number

ChiCTR2300078709.

Clinical outcomes of SMILE and WFG-LASIK used to treat myopia and astigmatism: A systematic review and meta-analysis

PURPOSE

To evaluate the safety, efficacy and postoperative visual quality of small incision lenticule extraction (SMILE) and Wavefront-Guided Laser in situ keratomileusis (WFG-LASIK) and to analyze their efficacy in correcting astigmatism.

METHODS

A systematic literature search was performed using Cochrane Collaboration methodology. Databases searched included PubMed, Embase, the Cochrane Library and Web of Science. RevMan software version 5.3.0 was used for meta-analysis.

RESULTS

A total of 976 eyes were included in 8 studies, of which 539 eyes underwent SMILE and 437 eyes underwent WFG-LASIK. There were no statistically significant differences in the proportion of eyes achieving uncorrected distance visual acuity of 20/20 or better (P=0.18), the proportion of eyes within±0.50 diopter of target refraction postoperatively (P=0.10), or the postoperative magnitude of cylinder (P=0.10). Regarding the Alpins vector analysis of astigmatism, there was no statistically significant difference in the surgical magnitude of error (P=0.09) between the two groups. WFG-LASIK has a lower surgical angle of error (P= 0.002) and higher surgical correction index of cylinder (P=0.03) than SMILE. In terms of aberrations, higher order aberrations (P=0.46), spherical aberrations (P=0.22) and trefoil (P=0.56) were not statistically different, while WFG-LASIK induced less coma than SMILE surgery (P=0.02).

CONCLUSION

Both SMILE and WFG-LASIK are safe and effective ways to correct myopia and astigmatism. Compared with SMILE, WFG-LASIK has a lower surgical angle of error, higher surgical correction index of cylinder and induces less coma.

Differences in ocular high order aberrations before and after small incision lenticule extraction for correction of myopia: a systematic review and meta-analysis

Objective

To examine the causes and factors that lead to high order aberration (HOA) during the treatment of myopia using small incision lenticule extraction (SMILE), as well as the differences between SMILE and other corneal refractive surgeries through a systematic review and meta-analysis.

Methods

A systematic search was conducted from January 2015 to February 2023 in Pubmed, Embase, Web of Science, and Google Scholar databases to gather relevant studies on SMILE and HOA. Studies meeting specific criteria were chosen, and clinical data was retrieved for analysis.

Results

This meta-analysis resulted in the inclusion of 19 studies involving 1,503 eyes. Pooled results showed significant induction of total HOA (tHOA, d = -0.21, p < 0.001), spherical aberration (SA, d = -0.11, p < 0.001) and coma aberration (CA, d = -0.18, p < 0.001) after SMILE compared to pre-SMILE, while no significant change in trefoil aberration (TA) was observed (d = -0.00, p = 0.91). There was a significantly lower induction of tHOA after SMILE compared to femtosecond laser-assisted in situ keratomileusis (FS-LASIK, d = 0.04, p < 0.001), and no significant difference was observed compared to wavefront aberration-guided (WFG) refractive surgery (d = 0.00, p = 0.75). There was also a significant association between different levels of myopia and astigmatism, duration of follow-up, lenticule thickness, and preoperative central corneal thickness (CCT) on the induction of tHOA after SMILE (p < 0.05), while the higher preoperative myopia group (sphere > -5D), lower preoperative astigmatism group (cylinder ≤ -1D), larger lenticule thickness group (lenticule thickness > 100 μm), shorter follow-up group (follow-up 1 month postoperatively) and the thicker CCT group (CCT > 550 μm) brought a significant induction of tHOA compared to the opposite comparison group (p < 0.001).

Conclusion

While SMILE can induce HOA significantly, it induces less HOA than FS-LASIK. Postoperative HOA following SMILE can be affected by factors such as myopia, astigmatism, lenticule thickness, CCT, and duration of follow-up. Future research should continue to explore techniques to decrease the induction of HOA by using this methodology.

Systematic review registration

https://www.crd.york.ac.uk/prospero/.

Photorefractive Keratectomy in Student Naval Aviators: Outcomes of the U.S. Navy Accessioning Study

PURPOSE

To present the outcomes of the U.S. Navy photorefractive keratectomy (PRK) accessioning study conducted between 2000 and 2005 that helped lead to the acceptance of laser vision correction within the U.S. aviation industry.

METHODS

In this prospective masked study, a total of 301 students who had PRK and underwent naval flight training were compared to 4,368 untreated peers. Three training pipelines were compared: propeller/jet transport, jet fighters, and helicopters. The evaluated metrics were flight and academic performance (assessed for the primary and advanced stage of the training as normalized Navy Standard Score [NSS]), as well as the student attrition rate from training.

RESULTS

The attrition rate was lower in the PRK group compared to controls (15.9% vs 23.2%; P = .004). In the primary stage of training, students who had PRK outperformed controls in flight training performance in the propeller/jet transport pipeline (average NSS after PRK: 52.4 ± 7.5 vs controls: 50.7 ± 6.4, P = .02), but the flight performance in the jet fighter and helicopter pipelines was comparable between the two groups. Academic performance in the primary stage of training was approximately 7% to 13% higher in students who had PRK for all training pipelines. During the advanced training stage, there was no difference in the flight performance between the groups in any of the presented pipelines. Academic performance was significantly better for students who had PRK in the helicopter pipeline (51.2 ± 11.0 vs 46.7 ± 11.7 P < .001) but comparable between the two groups in the remaining pipelines.

CONCLUSIONS

Refractive surgery did not have adverse effects on flight performance metrics. Pilots who had PRK had comparable or better outcomes than their untreated peers. [J Refract Surg. 2024:40(3):e173-e181.].

Comparison of the 1st Generation and 3rd Generation Wavefront-Guided LASIK for the Treatment of Myopia and Myopic Astigmatism

Purpose

To compare refractive, visual, and patient-reported outcomes associated with a 1st generation wavefront-guided (WFG) treatment with those associated with a 3rd generation WFG treatment.

Patients and Methods

This retrospective study included patients who underwent femtosecond laser-assisted in situ keratomileusis (LASIK) for myopia/myopic astigmatism. Two random stratified samples of patients who underwent either 1stgeneration (WaveScan, Johnson & Johnson Vision, Santa Ana, CA) or 3rd generation (iDesign 2.0, Johnson & Johnson Vision, Santa Ana, CA) treatment matched on preoperative refraction were compared (4290 eyes of 2145 patients in each group). One-month postoperative visual, refractive, and patient-reported outcomes were analyzed. Refractive and monocular visual acuity analyses were performed using one random eye of each patient.

Results

The percentage of eyes achieving 20/20 or better uncorrected vision was 91.3% (1958/2145) in the 1st generation group and 95.9% (2056/2145) in the 3rd generation group (p<0.01). Binocularly, the percentage of patients with 20/20 or better UDVA was 97.0% (2080/2145) and 99.2% (2127/2145) in the 1st and 3rd generation groups, respectively (p<0.01). The mean postoperative MSE was -0.01 ± 0.33 D in the 1st generation group and +0.19 ± 0.33 D in the 3rd generation group (p<0.01). Postoperative refractive astigmatism had a mean value of -0.20 ± 0.26 D and -0.18 ± 0.24 D in the 1st and 3rd generation groups, respectively (p<0.01). The mean correction index of refractive astigmatism was 1.09 ± 0.53 in the 1st generation group and 1.02 ± 0.38 in the 3rd generation group, p<0.01. The overall percentage of patients satisfied with vision was 92.8% (1991/2145 patients) in the 1st generation group and 97.3% (2087/2145 patients) in the 3rd generation group (p<0.01).

Conclusion

For the majority of postoperative variables, there were significant differences between 1st and 3rd generation treatments. The 3rd generation treatments had better visual acuity outcomes and higher patient satisfaction.

Topography-Guided LASIK: A Prospective Study Evaluating Patient-Reported Outcomes

Purpose

To evaluate patient-reported outcomes with a validated patient questionnaire following topography-guided LASIK (TG-LASIK).

Methods

Patients undergoing TG-LASIK using Phorcides analytic software were prospectively enrolled to receive an adapted Patient-Reported Outcomes with LASIK Symptoms and Satisfaction (PROWL) questionnaire before and 26-weeks after treatment. The main study outcome was the change in the Global Vision Satisfaction Index from the PROWL questionnaire.

Results

Forty-six patients underwent treatment and completed the modified PROWL questionnaire before and 26-weeks after TG-LASIK. The Global Vision Satisfaction Index from the modified PROWL questionnaire improved from 4.07 (3.87-4.26) to 5.00 (4.81-5.19) after the TG-LASIK treatment (p < 0.0001). The study population's binocular uncorrected distance visual acuity was 20/16, 20/12.5, and 20/10 or better in 100%, 87.0%, and 15.2% at 26 weeks post TG-LASIK, respectively.

Conclusion

Patient satisfaction as assessed with the modified PROWL questionnaire is very high after undergoing TG-LASIK using Phorcides analytic software. Patient-reported outcomes add another dimension when assessing treatment efficacy beyond change in visual acuity and corneal architecture, and specialists may consider incorporating such assessments into the consenting process and patient education at large.

Evaluation of Surgical Requirements and Competencies of the Saudi Ophthalmology Training Program in a Tertiary Eye Specialist Hospital- A Cross-Sectional Study

Purpose

To evaluate the adequacy of a Saudi ophthalmology training programs in achieving the competencies outlined by the Saudi Commission for Health Specialties (SCFHS) and the Accreditation Council for Graduate Medical Education (ACGME) and to assess resident satisfaction with their training.

Methods

A cross-sectional survey was sent electronically to all trainees (n=50) enrolled in the King Khaled Eye Specialist Hospital (KKESH) ophthalmology training program by email and messaging app (Whatsapp). The survey was sent between January 20, 2021, and January 30, 2021. It evaluated the level of satisfaction with surgical training and skills. The surgical logbooks of all trainees were extracted, and identifiers were removed. Then they were compared with SCFHS and ACGME curriculums for ophthalmology training.

Results

Out of 50 invitees, 47 returned the questionnaire. All trainees were confident they could meet surgical requirements by the end of their training. Most trainees were satisfied (n=29, 61.7%) with their performance in core competency requirements. There was no difference between female and male trainees' comfort levels when performing surgical steps in core competency requirements (P=0.2). Senior trainees seem more satisfied with their performance, especially in core competency requirements (P=0.087). All trainees practice at the wet lab and a virtual reality simulator to improve their skills. Obstacles faced during training were highlighted, including low exposure in the operating theater (n=18, 37.50%), competition on cases (n=5, 10.42%), attending surgeons not willing to teach (n=5, 10.42%), COVID-19 pandemic (n=5, 10.42%), and complex cases (n=4, 8.33%).

Conclusion

The outcomes of the current study indicate that trainees at KKESH were adequately satisfied with their surgical training in general. Also, competencies outlined by both the SCFHS and the ACGME were adequately fulfilled.

Topography-guided excimer laser ablation

PURPOSE OF REVIEW

Currently, the most commonly performed corneal refractive surgery is laser-assisted in-situ keratomileusis (LASIK). Customized forms of LASIK have been developed, which have allowed for improved outcomes and the enhanced correction of higher order aberrations (HOAs). This review discusses one form of custom LASIK, topography-guided LASIK, including factors involved in preoperative planning, and advantages and disadvantages compared with other forms of keratorefractive surgery.

RECENT FINDINGS

Various treatment-planning approaches addressing discrepancies between the refractive and topographic astigmatic magnitude and axis have been used successfully, although there is debate regarding a superior method in the literature.

SUMMARY

There are many forms of custom LASIK, which provide excellent outcomes. Topography-guided LASIK may be of particular use in highly aberrated corneas and may also provide outstanding outcomes in healthy eyes given its emphasis on treating the primary refractive surface of the eye.

Evolution of adaptive optics retinal imaging [Invited]

This review describes the progress that has been achieved since adaptive optics (AO) was incorporated into the ophthalmoscope a quarter of a century ago, transforming our ability to image the retina at a cellular spatial scale inside the living eye. The review starts with a comprehensive tabulation of AO papers in the field and then describes the technological advances that have occurred, notably through combining AO with other imaging modalities including confocal, fluorescence, phase contrast, and optical coherence tomography. These advances have made possible many scientific discoveries from the first maps of the topography of the trichromatic cone mosaic to exquisitely sensitive measures of optical and structural changes in photoreceptors in response to light. The future evolution of this technology is poised to offer an increasing array of tools to measure and monitor in vivo retinal structure and function with improved resolution and control.

Wavefront aberrometry repeatability and agreement—A comparison between Pentacam AXL Wave, iTrace and OPD‐Scan III

INTRODUCTION

To compare intrasession agreement and repeatability of wavefront aberration measurements from three different aberrometers obtained using Hartmann-Shack, ray tracing and automated retinoscopy methods, as well as their interdevice agreement.

METHODS

Three consecutive measurements were obtained using the Pentacam AXL Wave, the iTrace and the OPD-Scan III in 47 eyes of 47 patients. Wavefront refractions, root mean square of total aberrations (RMS total), RMS of higher-order aberrations (HOA) and second-, third- and fourth-order HOAs were exported for 4-mm pupils. Wavefront refractions were converted into vector components: M, J₀ and J₄₅ . Intrasession agreement and repeatability were evaluated using intraclass correlation coefficients (ICCs) and repeatability coefficients (RCs); interdevice agreement was assessed using the Bland-Altman method.

RESULTS

The intrasession agreement and repeatability of RMS HOA were comparable between the three devices; both the Pentacam AXL Wave and the OPD-Scan III had better intrasession agreement and repeatability for the RMS total than the iTrace (p ≤ 0.02). Intrasession repeatability for the majority of second- and third-order aberrations was better on the Pentacam AXL Wave than on the iTrace (p ≤ 0.01) and OPD-Scan III (p ≤ 0.04), although their agreement and repeatability in spherical aberration were comparable (p ≥ 0.24). Significant systematic differences and proportional bias were detected for almost all refraction power vectors and Zernike coefficients among the three devices.

CONCLUSIONS

In this study, all three devices provided good-to-excellent agreement for aberration measurements. Most of the individual Zernike's components were not exchangeable between different aberrometers. Their relative intrasession performance in agreement and repeatability varied significantly across different ocular aberration parameters.

Comparative analysis of the clinical outcomes between wavefront-guided and conventional femtosecond LASIK in myopia and myopia astigmatism

AIM

To compare the clinical outcomes of wavefront guided femtosecond LASIK (WFG LASIK) and conventional femtosecond LASIK (NWFG LASIK) in eyes with myopia and myopia astigmatism.

METHODS

This was a retrospective, nonrandomized, comparative investigation enrolling 236 eyes of 122 patients (18-50y) with low & moderate and high myopia. The WFG group including 97 eyes (50 patients) undergone WFG LASIK and the NWFG group including 139 eyes (72 patients) undergone conventional LASIK. Mean efficacy index, high order aberrations (HOAs), pupil size and the quality of visual questionnaire were evaluated 6mo postoperatively.

RESULTS

There is no difference between WFG group (-0.054±0.049 in logMAR) and NWFG group (-0.040±0.056) in uncorrected distance visual acuity (UDVA) postoperatively. The myopia astigmatism is higher in WFG group than that in NWFG group (P<0.05). However, the mean efficacy index (MEI) in the WFG group (1.09±0.106) is better than that in the NWFG group (1.036±0.124; P<0.001). Increased HOAs were observed in NWFG group (0.30±0.196) than that in WFG group (0.146±0.188; P<0.001). The pupil size is larger in WFG group (5.15±0.76 mm) than that in NWFG group (4.32±0.52 mm). The patients are satisfied with the clinical surgery, yet WFG group showed better visual quality using the questionnaire survey. Meanwhile, high myopia would result in worse MEI, HOAs and visual quality than low & moderate myopia.

CONCLUSION

WFG and NWFG FS-LASIK are both effective and safe procedures to correct low & moderate and high myopia, but WFG FS-LASIK gives a better postoperative MEI, aberrometric control and predictable outcome. Meanwhile, WFG FS-LASIK is better than NWFG FS-LASIK in correction of myopia astigmatism. Low & moderate myopia allow better clinical outcomes than high myopia using any surgical method.

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.].

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

PURPOSE

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.

SETTING

Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Guangzhou, China.

DESIGN

Prospective nonrandomized study.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Role of artificial tears with and without hyaluronic acid in controlling ocular discomfort following PRK: a randomized clinical trial

AIM

To compare outcomes of applying preservative free artificial tears (PFAT) with and without hyaluronic acid (HA) in early postoperative course following photorefractive keratectomy (PRK).

METHODS

In this triple-blinded randomized clinical trial, PRK procedure was performed on both eyes of 230 patients. Following PRK, patients were divided into three groups: the HA⁺ group, 44 patients PFAT containing HA; the HA^- group, 71 patients PFAT without HA were administered 5 times per day (every 4h); the third group, 115 patients received no PFAT before lens removal. On the 1^st and 4^th postoperative day, Visual Analogue Score (VAS) was utilized to evaluate patient's level of pain. Participants were asked to complete a questionnaire about the severity of eye discomfort ranked from 0 to 10 (0=no complaint; 10=most severe complaint experienced).

RESULTS

In eyes receiving PFAT with or without HA (Drop group), mean scores for epiphora, foreign body sensation, and blurred vision on the 1^st postoperative day were statistically lower (P<0.05). Filamentous keratitis (FK) was detected in 11 (4.7%) eyes, and recurrent corneal erosion (RCE) was observed in 5 (2.1%) eyes. In the control group, FK was noted in 16 (6.9%) eyes while 13 (5.6%) eyes had RCE and 5 (2.1%) eyes had corneal haze. The rate of complications was statistically lower in Drop group (P=0.009). However, the aforementioned scores were not statically different between HA⁺ and HA^- group one and two (P=0.29).

CONCLUSION

Following PRK, applying PFAT with and without HA yields faster visual recovery, decreases postoperative ocular discomfort and haze formation; however there is no additive effect for HA.

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

PURPOSE

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.

SETTING

Four clinical sites in the United States.

DESIGN

Double-arm, nonmasked, nonrandomized retrospective chart review.

METHODS

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).

RESULTS

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%).

CONCLUSIONS

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.

Complications of laser-assisted in situ keratomileusis

Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.

Three-Year Outcomes of Implantable Collamer Lens Followed by Excimer Laser Enhancement ("Bioptics") in the Treatment of High Myopic Astigmatism

Purpose

Describe three-year outcomes of spherical implantable Collamer lens (ICL) followed by excimer laser enhancement (bioptics) in eyes with high myopic astigmatism.

Patients and Methods

Retrospective case series of thirty-four cases that underwent bioptics enhancement at the Johns Hopkins Wilmer Eye Institute. All eyes had a preoperative sphere of −6.00 D or more with a cylinder of at least 2.00 D. Uncorrected and corrected distance visual acuity (UDVA and CDVA), manifest spherical equivalent refraction (MSE), ICL vault measurements and central corneal thickness (CCT) were collected. Endothelial cell counts (ECC), root mean square (RMS) of higher order aberrations (HOAs), adverse events and subsequent surgeries were also assessed.

Results

All patients had a minimum follow-up of 3 years. Preoperative UDVA was 2.29 ± 0.46 logMAR and improved to 0.03 ± 0.23 logMAR at 3 years (p<0.05). MSE was −12.30 ± 4.05 preoperatively and changed to −0.21 ± 0.46 at 3 years (p<0.05). The efficacy and safety indices were 1.28 ± 0.32 and 1.47 ± 0.27 at 3 years post-enhancement. HOA did not significantly change throughout the follow-up (p<0.05). Endothelial cell loss at 12 months was calculated at 5.7%. Two eyes required ICL exchange due to vault-related issues.

Conclusion

Bioptics offered excellent long-term safe, predictable, and efficient outcomes for high myopic astigmatism and can be considered an option if toric ICL is not available. Results confirm that wavefront-guided photoablation remains an excellent option to manage residual refractive error after phakic IOL.

[Excimer laser in keratoconus management]

Visual rehabilitation in keratoconus is a challenge, notably because of the significant irregular astigmatism and optical aberrations that it induces. Many surgical techniques have been developed in addition to, or in the case of failure of, spectacles and rigid gas permeable contact lenses: intracorneal ring segments, intraocular lenses, excimer laser and, as a last resort, keratoplasty. Excimer laser photoablates the cornea, allowing remodeling of its surface. There are various treatment modes (wavefront-optimized, wavefront-guided and topography-guided), allowing performance of a customized treatment if needed. Its use in keratoconus has been described since the 2000s, alone or in combination with other procedures. For example, the combination of photoablation and corneal cross linking, a technique that increases corneal rigidity and in so doing can slow or even stop the progression of keratoconus, proved its efficacy and safety in many studies, and various protocols have been described. A triple procedure, including intracorneal ring segments, excimer laser and cross linking, has also given some very promising results in progressive keratoconus, providing a significative improvement in visual acuity and topographic data. The combination of excimer laser and intraocular lenses remains a poorly explored lead that might provide some satisfactory results. The objective of this review is to summarize the recent data on excimer laser in keratoconus management.

Wavefront excimer laser refractive surgery for adults with refractive errors

BACKGROUND

Refractive errors (conditions in which the eye fails to focus objects accurately on the retina due to defects in the refractive system), are the most common cause of visual impairment. Myopia, hyperopia, and astigmatism are low-order aberrations, usually corrected with spectacles, contact lenses, or conventional refractive surgery. Higher-order aberrations (HOAs) can be quantified with wavefront aberration instruments and corrected using wavefront-guided or wavefront-optimized laser surgery. Wavefront-guided ablations are based on preoperative measurements of HOAs; wavefront-optimized ablations are designed to minimize induction of new HOAs while preserving naturally occurring aberrations. Two wavefront procedures are expected to produce better visual acuity than conventional procedures.

OBJECTIVES

The primary objective was to compare effectiveness and safety of wavefront procedures, laser-assisted in-situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) or laser epithelial keratomileusis (LASEK) versus corresponding conventional procedures, for correcting refractive errors in adults for postoperative uncorrected visual acuity, residual refractive errors, and residual HOAs. The secondary objective was to compare two wavefront procedures.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; 2019, Issue 8); Ovid MEDLINE; Ovid Embase; Latin American and Caribbean Health Sciences (LILACS); the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 6 August 2019. We imposed no restrictions by language or year of publication. We used the Science Citation Index (September 2013) and searched the reference lists of included trials to identify additional relevant trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing either wavefront modified with conventional refractive surgery or wavefront-optimized with wavefront-guided refractive surgery in participants aged ⪰ 18 years with refractive errors.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified 33 RCTs conducted in Asia, Europe and United States, totaling 1499 participants (2797 eyes). Participants had refractive errors ranging from high myopia to low hyperopia. Studies reported at least one of the following review-specific outcomes based on proportions of eyes: with uncorrected visual acuity (UCVA) of 20/20 or better, without loss of one or more lines of best spectacle-corrected visual acuity (BSCVA), within ± 0.50 diopters (D) of target refraction, with HOAs and adverse events. Study characteristics and risk of bias Participants were mostly women, mean age 29 and 53 years, and without previous refractive surgery, ocular pathology or systemic comorbidity. We could not judge risks of bias for most domains of most studies. Most studies in which both eyes of a participant were analyzed failed to account for correlations between two eyes in the analysis and reporting of outcomes. Findings For the primary comparison between wavefront (PRK or LASIK or LASEK) and corresponding conventional procedures, 12-month outcome data were available from only one study of PRK with 70 participants. No evidence of more favorable outcomes of wavefront PRK on proportion of eyes: with UCVA of 20/20 or better (risk ratio [RR] 1.03, 95% confidence interval (CI) 0.86 to 1.24); without loss of one or more lines of BSCVA (RR 0.94, 95% CI 0.81 to 1.09); within ± 0.5 D of target refraction (RR 1.03, 95% CI 0.86 to 1.24); and mean spherical equivalent (mean difference [MD] 0.04, 95% CI -0.11 to 0.18). The evidence for each effect estimate was of low certainty. No study reported HOAs at 12 months. At six months, the findings of two to eight studies showed that overall effect estimates and estimates by subgroup of PRK or LASIK or LASEK were consistent with those for PRK at 12 month, and suggest no difference in all outcomes. The certainty of evidence for each outcome was low. For the comparison between wavefront-optimized and wavefront-guided procedures at 12 months, the overall effect estimates for proportion of eyes: with UCVA of 20/20 or better (RR 1.00, 95% CI 0.99 to 1.02; 5 studies, 618 participants); without loss of one or more lines of BSCVA (RR 0.99, 95% CI 0.96 to 1.02; I2 = 0%; 5 studies, 622 participants); within ± 0.5 diopters of target refraction (RR 1.02, 95% CI 0.95 to 1.09; I2 = 33%; 4 studies, 480 participants) and mean HOAs (MD 0.03, 95% CI -0.01 to 0.07; I2 = 41%; 5 studies, 622 participants) showed no evidence of a difference between the two groups. Owing to substantial heterogeneity, we did not calculate an overall effect estimate for mean spherical equivalent at 12 months, but point estimates consistently suggested no difference between wavefront-optimized PRK versus wavefront-guided PRK. However, wavefront-optimized LASIK compared with wavefront-guided LASIK may improve mean spherical equivalent (MD -0.14 D, 95% CI -0.19 to -0.09; 4 studies, 472 participants). All effect estimates were of low certainty of evidence. At six months, the results were consistent with those at 12 months based on two to six studies. The findings suggest no difference between two wavefront procedures for any of the outcomes assessed, except for the subgroup of wavefront-optimized LASIK which showed probable improvement in mean spherical equivalent (MD -0.12 D, 95% CI -0.19 to -0.05; I2 = 0%; 3 studies, 280 participants; low certainty of evidence) relative to wavefront-guided LASIK. We found a single study comparing wavefront-guided LASIK versus wavefront-guided PRK at six and 12 months. At both time points, effect estimates consistently supported no difference between two procedures. The certain of evidence was very low for all estimates. Adverse events Significant visual loss or optical side effects that were reported were similar between groups.

AUTHORS' CONCLUSIONS

This review suggests that at 12 months and six months postoperatively, there was no important difference between wavefront versus conventional refractive surgery or between wavefront-optimized versus wavefront-guided surgery in the clinical outcomes analyzed. The low certainty of the cumulative evidence reported to date suggests that further randomized comparisons of these surgical approaches would provide more precise estimates of effects but are unlikely to modify our conclusions. Future trials may elect to focus on participant-reported outcomes such as satisfaction with vision before and after surgery and effects of remaining visual aberrations, in addition to contrast sensitivity and clinical outcomes analyzed in this review.

Ectatic diseases

Ectatic corneal disease (ECD) comprises a group of disorders characterized by progressive thinning and subsequent bulging of the corneal structure. Different phenotypes have been recognized, including keratoglobus, pellucid marginal degeneration (PMD), and keratoconus (KC). Keratoconus has been widely investigated throughout the years, but the advent of laser refractive surgery boosted an immediate need for more knowledge and research about ectatic diseases. This article discusses nomenclature of ectatic disease, etiology and pathogenesis, along with treatment options, with special focus ok KC and forme fruste keratoconus.

Visual and Refractive Outcomes with a New Topography-integrated Wavefront-guided Lasik Procedure

PURPOSE

To evaluate the clinical outcomes of laser in situ keratomileusis (LASIK) using a new approach for the calculation of the ablation profile based on wavefront vertexing from pupil plane to corneal.

METHODS

One hundred eyes of 50 patients (age, 21-41 years) with low and moderate myopia were enrolled in this prospective case series. All of them underwent topography-integrated wavefront-guided (TI-WFG) LASIK using the STAR S4IR excimer laser platform (Johnson & Johnson Vision). Visual, refractive, ocular aberrometric, ocular scattering index (OSI) and patient satisfaction outcomes were evaluated after a 90-day follow-up period. Astigmatic changes were evaluated by vector analysis.

RESULTS

A significant reduction in sphere and cylinder (p < .001) was observed, with a significant improvement in uncorrected (UDVA) and corrected distance visual acuity (CDVA) (p < .001). Postoperative spherical equivalent was within ±0.50 and ±1.00 D in 91.1% (82/90) and 98.9% (89/90) of eyes, respectively. UDVA was 20/20 or better in 98.9% (89/90) of eyes. A total of 50.0% (45/90) of eyes gained 1 line of CDVA. Mean postoperative astigmatic correction index and angle of error were 1.01 ± 0.56 and 0.17 ± 0.18º. Postoperative high-order aberrometric coefficients were below 0.50 μm in 92.2% (83/90) of eyes. Mean postoperative OSI was 0.71 ± 0.44. All patients referred to be satisfied with the final outcomes and would recommend the procedure to their friends and relatives.

CONCLUSIONS

TI-WFG LASIK is a new approach for myopia and myopic astigmatism correction, with preservation of the ocular optical quality and high level of patient satisfaction associated.

Comparison of refractive outcomes and high-order aberrations after small incision lenticule extraction and wavefront-guided femtosecond-assisted laser in situ keratomileusis for correcting high myopia and myopic astigmatism

PURPOSE

To compare the results of using small incision lenticule extraction (SMILE) and wavefront-guided femtosecond-assisted laser in situ keratomileusis (WFG FS-LASIK) to correct high myopia and myopic astigmatism.

MATERIAL AND METHODS

The 94 eyes of 47 patients with high myopia or myopic astigmatism, if not both, who had undergone SMILE were compared with the 94 eyes of 47 patients with high myopia or myopic astigmatism, also if not both, who had undergone WFG FS-LASIK. Only eyes with high myopic or myopic astigmatism errors greater than - 6.0 diopter (D) spherical refraction and 0-3 D cylindrical refraction were included. Values of uncorrected distance visual acuity, corrected distance visual acuity, efficacy index, safety index, predictability, and high-order aberration between the patient groups were compared.

RESULTS

The SMILE and WFG FS-LASIK groups did not significantly differ according to sex or age. Values of preoperative and postoperative spherical refraction, cylindrical refraction, spherical equivalent, uncorrected distance visual acuity, and corrected distance visual acuity between the groups also did not significantly differ nor did values of predictability, the efficacy index, or the safety index. SMILE induced more coma and trefoil (p < 0.001), whereas WFG FS-LASIK induced more spherical aberration (p < 0.001).

CONCLUSION

Both SMILE and WFG FS-LASIK are efficient, safe, predictable procedures for correcting high myopia and myopic astigmatism. SMILE may induce more coma and trefoil, whereas WFG FS-LASIK may induce more spherical aberration.

Correlation between higher-order aberrations and visual acuity recovery (CoHORT) after spectacles treatment for pediatric refractive amblyopia: A pilot study using iDesign measurement

Purpose

To determine the correlation between higher-order aberrations (HOAs) and best-corrected visual acuity (BCVA) recovery speed after spectacles treatment using iDesign measurements in refractive amblyopic children.

Methods

This is a prospective case series. Children aged from 3 to 7 years with refractive amblyopia (Landolt C equivalent < 0.8) were recruited. All participants were followed for at least 6 months after full correction of the refraction error by spectacles. The HOAs were measured using iDesign before and after cycloplegia at first visit and at 3-month intervals. Then correlation between BCVA recovery after treatment for 6 months and HOAs was determined.

Results

We analyzed 24 eyes of 12 children (mean age, 4.5 years). Baseline mean BCVA was logarithm of minimal angle of resolution (logMAR) 0.335 (Landolt C equivalent 0.46), which improved to logMAR 0.193 (Landolt C equivalent 0.64) after treatment with full-correction spectacles for 6 months. The amblyopic eye BCVA recovery was negatively correlated with tetrafoil with/without cycloplegia (P = 0.006 and 0.022, respectively) and trefoil with cycloplegia (P = 0.049).

Conclusions

trefoil and tetrafoil measured with iDesign negatively correlates with the BCVA recovery speed of refractive amblyopic eyes after spectacles treatment in this pilot study. The current study results may aid in further investigation for diagnosis and treatment of refractory refractive and idiopathic amblyopia.

Risk factors for early flap misalignment following microkeratome-assisted laser in situ keratomileusis: A retrospective large database analysis

PURPOSE

To determine factors associated with early flap misalignment following microkeratome-assisted laser in situ keratomileusis.

MATERIALS AND METHODS

This retrospective study included the right eyes of consecutive patients who underwent laser in situ keratomileusis procedure between 2005 and 2016 at Care-Vision Laser Centers, Tel-Aviv, Israel. Patients were divided into two groups according to whether or not they subsequently developed early flap misalignment.

RESULTS

A total of 14,582 eyes (mean age of patients: 32.4 ± 10.3 years) were included. Post-laser in situ keratomileusis early flap misalignment developed in 158 eyes (1.1%). Misalignment was more frequent during the spring (32.3% vs 22.8%, p = 0.003) and in a higher operating room temperature (23.34 ± 1.06 vs 22.98 ± 1.26, p < 0.001). In addition, in the misalignment group, there was a higher rate with the of use of the a Moria M2 microkeratome (rather than sub-Bowman's keratomileusis microkeratome) head (55.2% vs 40.5%, respectively, p < 0.001). In a multivariable analysis adjusted for surgeon and year of surgery, high operating room temperature (odds ratio = 1.22, p = 0.006), treatment zone of 9.0 mm (as opposed to smaller treatment zones, odds ratio = 1.54, p = 0.04), and springtime (odds ratio = 1.58, p = 0.02) were associated with flap misalignment. There was a significant difference in misalignment rates between surgeons (p = 0.02).

CONCLUSION

This study found that larger treatment zones, higher operating room temperature, operating during the spring, and the use of Moria M2 microkeratome were associated with increased flap misalignment rates. The association with operating room temperature and seasonal variation is of interest and merits further research.

Comparison of Wavefront-Optimized Ablation and Topography-Guided Contoura Ablation With LYRA Protocol in LASIK

PURPOSE

To compare the refractive outcomes and aberration data analysis of wavefront-optimized (WFO) ablation and topography-guided Contoura ablation (TGCA) (Contoura on the WaveLight laser; WaveLight GmbH, Erlangen, Germany) in patients who had laser-assisted in situ keratomileusis (LASIK) for myopia or myopic astigmatism.

METHODS

In this comparative contralateral eye study, patients who underwent LASIK with TGCA in one eye and with WFO ablation in the fellow eye were analyzed. Aberration measurements and corneal topography were analyzed using the WaveLight Oculyzer II diagnostic device (Alcon Laboratories, Inc., Fort Worth, TX). Total corneal higher order aberrations (HOAs) including vertical and oblique astigmatism (Z² ₂, Z² _-2), coma (Z³ ₁, Z³ _-1), trefoil (Z³ ₃, Z³ _-3), spherical aberration, and Q value were analyzed. These measurements were taken preoperatively and 3 months postoperatively.

RESULTS

This study comprised 32 patients. There were no significant differences between both procedures according to postoperative uncorrected and corrected distance visual acuity values, refractive errors, and manifest refraction spherical equivalents within ±0.50 diopters (D) of emmetropia (P > .05). The preoperative corneal HOAs and Q values were also similar between the groups (P > .05). At 3 months postoperatively, the vertical and horizontal coma values in the WFO ablation group were statistically significantly higher compared to the TGCA group (P = .013 and .020, respectively). Less stromal tissue was ablated in the TGCA group compared to the WFO ablation group (P < .001).

CONCLUSIONS

Although WFO ablation and TGCA protocols had statistically similar visual outcomes, the TGCA protocol was associated with a significantly lower induction in vertical and horizontal coma and smaller amount of tissue ablation compared to WFO ablation. [J Refract Surg. 2019;35(4):222-229.].