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.

Outcome comparison between wavefront-guided and wavefront-optimized photorefractive keratectomy: A systematic review and meta-analysis

Photorefractive keratectomy (PRK) eye surgery is widely used for patients at risk for corneal ectasia to maintain an aspheric corneal shape. Wavefront-guided (WFG) ablation profile was designed to reduce pre-existing higher-order aberrations (HOA). We aimed to compare the corneal aberrations and visual outcomes between WFG and Wavefront Optimized (WFO) PRK in patients with myopia. Eight randomized clinical trials were included. We searched PubMed, Scopus, Web of Science and CENTRAL at March 2020, and updated the search in September 2020 using relevant keywords, The data were extracted and pooled as Mean Difference (MD) with a 95% Confidence Interval (CI), using Review Manager software (version 5.4). Pooled results showed no significance between Uncorrected Distance Visual Acuity (UDVA) and Corrected Distance Visual Acuity (CDVA) between both groups underwent WFG and WFO PPR after three months follow up (MD = - 0.03; 95% CI: [-0.06, 0.00]; P = 0.07), (MD = - 0.02; 95% CI: [-0.04, 0.01]; P = 0.22) respectively. Although, no significant difference between mean manifest cylinder after three and 12 months follow up, but the total MD for mean manifest cylinder difference was significantly lower with the WFG treatment method (MD = - 0.12, (95% CI: [0.23:-0.01], P = 0.03). This shows a slight advantage of the WFG over the WFO method. The visual performance showed similarity and excellent refractive outcomes in both WFO and WFG PRK. No significant statistical differences between the two approaches. On further comparison, there was a slight advantage of the WFG over the WFO method.

One-Year Outcomes From a Prospective, Randomized, Eye-to-Eye Comparison of Wavefront-Guided and Wavefront-Optimized PRK in Myopia

PURPOSE

To compare wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) in patients with myopia using objective and self-reported quality of vision outcomes.

METHODS

A total of 40 eyes from 20 participants were prospectively randomized to receive WFG or WFO PRK with the WaveLight Allegretto Eye-Q 400-Hz excimer laser (Alcon Laboratories, Inc., Fort Worth, TX). The primary outcome measured was uncorrected distance visual acuity (UDVA) at 12 months postoperatively. Secondary outcome measures included corrected distance visual acuity (CDVA), less than 5% and less than 25% contrast visual acuity, changes in higher order aberrations (HOAs), and self-reported quality of vision. Patients completed a validated, Rasch-tested, linear-scaled 30-item questionnaire assessing the quality of vision and visual symptoms preoperatively and at each visit.

RESULTS

There was no statistically significant difference (P > .05) between the WFG and WFO groups in the frequency of attaining a refractive error within ±0.25 diopters of emmetropia, achieving postoperative UDVA of 20/16 or better or 20/20 or better, losing one or two or more lines or maintaining their preoperative CDVA, or differences in UDVA, CDVA, low contrast acuity, or HOAs. None of the measured quality of vision parameters exhibited statistically significant differences between the groups preoperatively or at 12 months postoperatively (all P > .05). The WFG and WFO groups each showed significant improvement in multiple subjective measures compared to pretreatment values in the same eye. A total of 12.5% of patients preferred their WFG PRK eye, 31.25% preferred their WFO PRK eye, and 56.25% had no preference at 12 months postoperatively.

CONCLUSIONS

WFG and WFO PRK using the Alcon Wave-Light Allegretto Eye-Q 400-Hz excimer laser platform provide similar results and self-reported visual symptoms in myopic eyes at 12 months postoperatively. [J Refract Surg. 2020;36(3):160-168.].

Prospective, Randomized, Contralateral Eye Comparison of Wavefront-Guided and Wavefront-Optimized Laser in Situ Keratomileusis

PURPOSE

To compare outcomes in wavefront-optimized (WFO) laser in situ keratomileusis (LASIK) to high-resolution wavefront-guided (WFG) LASIK.

DESIGN

Randomized, fellow eye controlled, clinical trial.

METHODS

A total of 200 eyes of 100 patients with myopia or compound myopic astigmatism undergoing bilateral LASIK between October 2015 and February 2017 underwent wavefront-optimized (WFO) LASIK in 1 eye and wavefront-guided (WFG) LASIK in the fellow eye. Each eye was evaluated for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), contrast sensitivity, refractive error, and wavefront aberrometry. Outcome measurement primarily UDVA at 12 months. Secondary outcomes were safety, predictability, stability, refractive error, CDVA, contrast sensitivity, and higher-order aberrations at 12 months.

RESULTS

WFG LASIK had higher levels of supervision and better contrast sensitivity compared to WFO. Both types had excellent postoperative UDVA results, without a significant difference in either mean UDVA or frequency of achieving a specified UDVA, for example, 20/16 or better (all P > 0.05). The mean gain in lines of CDVA was significantly higher in the WFG than in the WFO group (0.80 ± 0.75 vs 0.62 ± 0.72, respectively; P = 0.04). The WFG cohort had significantly better contrast sensitivity for mean and frequency of achieving >20/40 for <5% low-contrast sensitivity (37.1%; 95% confidence interval [CI], 27.5-46.7 vs 24.7%; 95% CI, 16.2-33.3, respectively; P = 0.01) and >20/32 for <25% low-contrast sensitivity (10.3%; 95% CI, 4.3-16.4 vs 4%, respectively; 95% CI, 0.0-8.1, respectively; P = 0.04). The WFO group had a significantly higher frequency of <0.25 diopters (D) of refractive astigmatism at 12 months (82.5%; 95% CI, 75.0-90.0; vs 72.1%, respectively; 95% CI, 63.2-81.2; P = 0.02) but not <0.50 D (95.6%; 95% CI, 91.9-99.8; vs 96.9, respectively; 95% CI, 93.5-100; P = 0.61). The WFG group was significantly closer to emmetropia for both sphere and spherical equivalents at all time points. Trefoil was significantly lower in the WFG group and was also significantly lower than preoperative measurements.

CONCLUSIONS

Wavefront-optimized and high-resolution wavefront-guided LASIK achieve excellent visual outcomes. Nonetheless, treatments based on a high-resolution aberrometer appear to offer superior results in some regards.

Photorefractive keratectomy combined with corneal wavefront-guided and hyperaspheric ablation profiles to correct myopia

PURPOSE

To evaluate the effects of photorefractive keratectomy (PRK) combined with corneal wavefront-guided ablation profiles and hyperaspheric ablation profiles on changes in higher-order aberrations (HOAs).

SETTING

Yonsei University College of Medicine and Eyereum Clinic, Seoul, South Korea.

DESIGN

Comparative observational case series.

METHODS

Medical records of patients who had corneal wavefront-guided hyperaspheric PRK, corneal wavefront-guided mild-aspheric PRK, or non-corneal wavefront-guided mild-aspheric PRK were analyzed. The logMAR uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent (MRSE), and changes in corneal aberrations (root-mean-square [RMS] HOAs, spherical aberration, coma) were evaluated 1, 3, and 6 months postoperatively.

RESULTS

The records of 61 patients (96 eyes) were reviewed. There was no statistically significant difference in logMAR UDVA or MRSE between the 3 groups at any timepoint. Corneal RMS HOAs were significantly smaller in the corneal wavefront-guided hyperaspheric group and the corneal wavefront-guided mild-aspheric group than in the noncorneal wavefront-guided mild-aspheric group at each timepoint. Corneal spherical aberration was significantly smaller for corneal wavefront-guided hyperaspheric PRK than for noncorneal wavefront-guided mild-aspheric PRK 6 months postoperatively. Changes in corneal spherical aberration (preoperatively and 6 months postoperatively) in corneal wavefront-guided hyperaspheric PRK were significantly smaller than in corneal wavefront-guided mild-aspheric PRK (P = .046). Corneal coma was significantly smaller with corneal wavefront-guided hyperaspheric PRK and corneal wavefront-guided mild-aspheric PRK than with noncorneal wavefront-guided mild-aspheric PRK 3 months and 6 months postoperatively.

CONCLUSION

Corneal wavefront-guided hyperaspheric PRK induced less corneal spherical aberration 6 months postoperatively than corneal wavefront-guided mild-aspheric PRK and noncorneal wavefront-guided mild-aspheric PRK.

FINANCIAL DISCLOSURE

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

Visual Outcomes and Higher Order Aberrations Following LASIK on Eyes with Low Myopia and Astigmatism

Background:

Laser-Assisted in situ Keratomileusis (LASIK) can induce corneal aberrations that can impact vision and patient satisfaction. Recent developments in laser technologies have helped minimise these aberrations.

Objective:

To assess the quality of vision and change in Higher-Order Aberrations (HOAs) following wavefront-optimized LASIK in low-myopic astigmatic patients.

Methods:

LASIK was performed on a total of 76 eyes in patients with myopia <4.0 D and cylinder <2.0 D using the WaveLight® EX500 excimer and FS200 femtosecond laser platform. Visual acuity, contrast sensitivity and HOAs were measured at 1 and 3 months postoperatively and compared to preoperative values. Subjective quality of vision was assessed pre- and postoperatively using a VF14 questionnaire.

Results:

Mean postoperative Spherical Equivalent (SE) was -0.09 ± 0.26 µm with 95% of patients within ± 0.5 D of attempted SE. Postoperative uncorrected distance visual acuity was 20/20 or better for 96% of patients. Contrast sensitivity increased against horizontal and vertical gratings at all spatial frequencies except for vertical gratings at 18 cycles/degree. Spherical aberration and total HOA increased by 0.085 µm and 0.13 µm respectively. The mean VF14 score increased from 89.2 ± 16.7% to 99 ± 1.4% postoperatively.

Conclusion:

LASIK performed using the WaveLight® EX500 excimer and WaveLight® FS200 laser platform provided improved contrast sensitivity and visual acuity with minimal introduction of HOAs, making it a suitable platform for low myopic astigmatic patients.

Comparison of femtosecond and excimer laser platforms available for corneal refractive surgery

PURPOSE OF REVIEW

The evolution of laser technology has left today's refractive surgeon with a choice between multiple laser platforms. The purpose of this review is to compare currently available femtosecond and excimer laser platforms, providing a summary of current evidence.

RECENT FINDINGS

Femtosecond lasers create LASIK flaps with better accuracy, uniformity, and predictability than mechanical microkeratomes. Newer higher-frequency femtosecond platforms elicit less inflammation, producing better visual outcomes. SMILE achieved similar safety, efficacy, and predictability as LASIK with greater preservation of corneal nerves and biomechanical strength. The emergence of wavefront technology has resulted in improved excimer laser treatments. Comparisons of wavefront-guided and wavefront-optimized treatments suggest that there is an advantage to using wavefront-guided platforms in terms of visual acuity and quality of vision. Topography-guided ablations are another well tolerated and effective option, especially in eyes with highly irregular corneas.

SUMMARY

Advances in femtosecond and excimer laser technology have not only improved the safety and efficacy of refractive procedures, but have also led to the development of promising new treatment modalities, such as SMILE and the use of wavefront-guided and topography-guided ablation. Future studies and continued technological progress will help to better define the optimal use of these treatment platforms.

Quality of Vision After Wavefront-Guided or Wavefront-Optimized LASIK: A Prospective Randomized Contralateral Eye Study

PURPOSE

To compare the effect of wavefront-guided and wavefront-optimized LASIK using different laser platforms on subjective quality of vision.

METHODS

The dominant eyes of 55 participants with myopia were randomized to receive either wavefront-guided LASIK treatment by the VISX Star S4 IR Custom-Vue excimer laser system (Abbott Medical Optics, Inc., Santa Clara, CA) or wavefront-optimized treatment by the WaveLight Allegretto Wave Eye-Q 400-Hz excimer laser system (Alcon Laboratories, Inc., Fort Worth, TX), whereas the fellow eye had the alternate laser treatment. Patients completed a questionnaire assessing quality of vision and visual symptoms (daytime and nighttime glare, daytime and nighttime clarity, halos, haze, fluctuating vision, and double vision) preoperatively and at postoperative months 1, 3, 6, and 12.

RESULTS

At 3, 6, and 12 months postoperatively, there was no significant difference in any individual symptom between the wavefront-guided and wavefront-optimized groups, although at 12 months wavefront-guided eyes trended toward having more excellent vision (wavefront-guided vs wavefront-optimized; 2.26 vs 2.43; P = .039). In the subgroup of patients with preoperative root mean square (RMS) higher order aberrations (HOAs) less than 0.3 µm in both eyes, the wavefront-optimized group demonstrated a trend toward worsened nighttime clarity (P = .009), daytime clarity (P = .015), and fluctuating vision (P = .046), and less excellent vision (P = .009) at 12 months.

CONCLUSIONS

Twelve months after surgery, most patients' self-reported visual symptoms were similar in eyes receiving wavefront-guided or wavefront-optimized LASIK. In general, 36% of patients preferred wavefront-guided LASIK, 19% preferred wavefront-optimized LASIK, and 45% had no preference at 12 months. The wavefront-guided preference was more pronounced in patients with lower baseline HOAs (RMS < 0.3 µm).

Wavefront-guided versus wavefront-optimized photorefractive keratectomy: Clinical outcomes and patient satisfaction

PURPOSE

To compare visual outcomes following Visx Star S4 Customvue wavefront-guided and Allegretto Wave Eye-Q 400 Hz wavefront-optimized photorefractive keratectomy (PRK).

SETTING

Warfighter Refractive Eye Surgery Program and Research Center, Fort Belvoir, Virginia, and Walter Reed National Military Medical Center, Bethesda, Maryland, USA.

DESIGN

Prospective randomized clinical trial.

METHODS

Active-duty United States military soldiers were randomized to have wavefront-guided (Visx Star S4 Customvue) or wavefront-optimized PRK. Participants were followed up to 12 months postoperatively. Primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest spherical equivalent (SE). Secondary outcome measures included refractive astigmatism, higher-order aberrations (HOAs), contrast sensitivity, subjective visual complaints, and patient satisfaction.

RESULTS

The study evaluated 108 soldiers (mean age 30.3 years ± 6.3 [SD]; mean manifest SE -3.51 ± 1.63 D). At 12 months postoperatively, achieved UDVA, CDVA, manifest SE, and refractive astigmatism were comparable between wavefront-guided and wavefront-optimized groups (P > .213). Spherical aberration and total HOAs significantly increased from baseline in both groups (P < .006). The change in coma, trefoil, spherical aberration, and total HOAs (P > .254) were comparable between groups. There were fewer losses of photopic low-contrast visual acuity (LCVA) at 5% contrast after wavefront-guided compared to wavefront-optimized treatment (P = .003). There was no significant difference between treatment groups in visual symptoms, overall vision expectation, and satisfaction (P > .075).

CONCLUSION

Wavefront-guided treatment offered a small advantage in photopic LCVA. Refractive outcomes, HOAs, self-reported visual difficulties, overall vision expectation, and satisfaction were otherwise comparable between wavefront-guided and wavefront-optimized treatments.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Wavefront-optimized surface retreatments of refractive error following previous laser refractive surgery: a retrospective study

Background

Retreatments are sometimes necessary to correct residual or induced refractive errors following refractive surgery. Many different combinations of primary treatment methods and retreatment techniques have been studied, however, few studies have investigated wavefront-optimized (WFO) technology for retreatment following primary refractive surgery. This study aimed to report the outcomes of WFO photorefractive keratectomy (PRK) retreatments of refractive error following previous laser refractive surgery with PRK, laser in situ keratomileusis (LASIK), or laser-assisted subepithelial keratectomy (LASEK).

Methods

We reviewed records of patients who underwent WFO PRK retreatments using the Allegretto Wave Eye-Q 400 Hz Excimer Laser System (Alcon Surgical) between January 2008 and April 2011 at Walter Reed Army Medical Center and Madigan Army Medical Center. Outcomes were recorded in terms of uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent (MRSE), corrected distance visual acuity (CDVA), and complications at 1 month (M), 3 M, and 6 M post-op.

Results

Seventy-eight patients (120 eyes) underwent WFO PRK retreatment during the study period. Primary surgery was surface ablation in 87 eyes (78 PRK, 9 LASEK) and LASIK in 33 eyes. The mean spherical equivalent before retreatment was −0.79 ± 0.94 D (−3.00 to 1.88 D). UDVA was ≥ 20/20 in 69 eyes (60.0 %) at 1 M, 54 eyes (71.1 %) at 3 M, and 27 eyes (73.0 %) at 6 M follow-up. MRSE was within ±0.50 D of emmetropia in 78 eyes (67.8 %) at 1 M, 59 eyes (77.6 %) at 3 M, and 25 eyes (67.6 %) at 6 M follow-up. CDVA was maintained within ±1 line of pre-op in 113 of 115 eyes (98.3 %) at 1 M, 74 of 76 eyes (97.4 %) at 3 M, and 37 eyes (100 %) at 6 M follow-up.

Conclusion

Although follow-up was limited beyond 3 M, WFO PRK retreatments in patients with residual refractive error may be a safe and effective procedure. Further studies are necessary to determine the long-term safety and stability of outcomes.

Retrospective Analysis Comparing the Preoperative and Postoperative "Q" Values for 2 Different Lasers in Refractive Surgery

PURPOSE

To compare the presurgical and postsurgical corneal asphericity, or "Q value," between VISX Wavefront-guided treatment and Allegretto Wave Wavefront-optimized treatment in photorefractive keratectomy for the correction of myopia.

METHODS

This is a retrospective database analysis performed at the Joint Warfighter Refractive Surgery Center, Lackland Air Force Base, TX. All data were accessed through the Institutional Review Board-approved Joint Warfighter Refractive Surgery Center database. Fifty-one patient records (102 eyes) were reviewed to determine the change in the Q value after photorefractive keratectomy for the correction of myopia.

RESULTS

The average change in the Q value per diopter of treatment sphere over the entire study population was 0.12 (±0.04) for Allegretto and 0.14 (±0.04) for VISX (P = 0.004). There was no statistical difference among the preoperative and postoperative best-corrected visual acuities (BCVAs), low-contrast BCVA (BCVA 5%), or quality of vision complaints between both platforms.

CONCLUSIONS

Low to moderate myopic correction with the Allegretto laser was associated with a smaller change in the Q value per diopter of treatment and therefore more closely maintained the original prolate shape of the cornea when compared with VISX. No difference in the postoperative visual outcome between both groups was detected.

Vector analysis of 1-year astigmatic outcomes from a prospective, randomized, fellow eye comparison of wavefront-guided and wavefront-optimized LASIK in myopes

PURPOSE

To compare the astigmatic outcomes of LASIK with a single excimer laser platform using either wavefront-guided (WFG) or wavefront-optimized (WFO) modes.

METHODS

Sixty-eight eyes of 34 patients underwent LASIK for myopia with the Wavelight Allegretto Eye-Q 400-Hz laser platform (Alcon Laboratories, Inc., Hüenberg, Switzerland). One eye underwent WFG-LASIK and the contralateral eye underwent WFO-LASIK. Alpins vector analysis of astigmatism was performed using manifest refraction measured preoperatively and 12 months postoperatively and vertexed to the corneal plane. Eyes were stratified for subgroup analysis based on preoperative manifest astigmatism.

RESULTS

WFG-LASIK and WFO-LASIK were similar with regard to surgically induced astigmatism, difference vector, magnitude of error, correction index, flattening index, and index of success. The angle of error was 80% less in the WFG group compared to the WFO group (1.92° ± 0.67º vs 9.66° ± 3.7º, P = .04).

CONCLUSIONS

WFG-LASIK and WFO-LASIK using the Alcon WaveLight Allegretto Eye-Q 400-Hz excimer laser platform produce similar astigmatic results in myopic patients; however, the WFG mode may produce slightly more predictable astigmatic corrections.

Comparison of visual outcomes after variable spot scanning ablation versus wavefront-optimized myopic LASIK

PURPOSE

To compare the refractive and visual outcomes of variable spot scanning ablation versus the wavefront-optimized ablation for myopia and myopic astigmatism.

METHODS

Fifty patients with myopia who underwent LASIK (100 eyes) were divided into two equal groups. Myopic correction performed using the variable spot scanning (VSS) ablation with the VISX STAR S4/IR platform (Abbott Medical Optics, Inc., Santa Ana, CA) (VSS group) and wavefront-optimized (WFO) ablation profile with the WaveLight Allegretto Wave Eye-Q platform (Alcon Laboratories, Inc., Fort Worth, TX) (WFO group). Manifest refraction, uncorrected distance visual acuity, and corrected distance visual acuity were obtained preoperatively and 1 day and 1 and 3 months postoperatively. Wavefront measurement and contrast sensitivity testing were done preoperatively and 3 months postoperatively.

RESULTS

Postoperative mean refractive spherical equivalent was -0.14 ± 0.2 diopters for the VSS group and -0.15 ± 0.28 diopters for the WFO group. Forty-eight eyes of the VSS group and 47 eyes of the WFO group were within ±0.5 diopters. Postoperative mean corrected distance visual acuity was 1.05 ± 0.13 for the VSS group and 1.06 ± 0.12 for the WFO group. The postoperative uncorrected distance visual acuity was 1.01 ± 0.16 for the VSS group and 1.01 ± 0.11 for the WFO group. The safety index was 1.12 for the VSS group and 1.06 for the WFO group, whereas the efficacy index was 1.07 for the VSS group and 1.01 for the WFO group. The mean induced positive spherical aberration was 0.041 ± 0.046 µm for the VSS group and 0.195 ± 0.171 µm for the WFO group (P < .001). Mesopic contrast sensitivity testing showed no statistically significant differences between groups at all tested spatial frequencies.

CONCLUSIONS

Both VSS and WFO treatments showed similar refractive and visual outcomes. Both induced significant positive spherical aberration, significantly more with WFO.

Wavefront-guided versus wavefront-optimized laser in situ keratomileusis for patients with myopia: a prospective randomized contralateral eye study

PURPOSE

To compare the clinical outcomes of wavefront-guided and wavefront-optimized laser in situ keratomileusis (LASIK).

DESIGN

Prospective, randomized, fellow-eye-controlled study.

METHODS

The setting was a single academic institution. The study population included 110 eyes of 55 patients with myopia with and without astigmatism. One eye of each patient was randomized to undergo wavefront-guided LASIK by the AMO Visx CustomVue S4 IR excimer laser system; the fellow eye received wavefront-optimized LASIK by the Alcon Allegretto Wave Eye-Q 400 Hz excimer laser system. Corneal flaps were constructed using the Intralase FS 60 Hz femtosecond laser. Patients were followed at postoperative months 1, 3, 6, and 12. The study's main outcome measures were uncorrected visual acuity, stability of refractive correction, contrast sensitivity, and wavefront aberrometry.

RESULTS

After 12 months, LASIK eyes had achieved visual acuity of 20/12.5 or better (30 eyes, 56%) in the wavefront-guided group compared to those receiving wavefront-optimized treatment (22 eyes, 41%) (P = 0.016). Average spherical equivalent refractions were -0.13 ± 0.46 diopters in wavefront-guided eyes whereas in wavefront-optimized eyes the refractions were -0.41 ± 0.38 diopters at 12 months. Wavefront-guided eyes also achieved better best-corrected visual acuity at both the 5% and 25% contrast levels (P = 0.022 and P = 0.004, respectively). There were no differences in levels of residual astigmatism (P = 0.798) or in higher order aberrations (P = 0.869).

CONCLUSIONS

Both wavefront-guided and wavefront-optimized treatments are able to correct myopia safely and effectively in eyes with and without astigmatism. However, wavefront-guided treatment platforms appear to offer significant advantages in terms of residual refractive error, uncorrected distance acuity and contrast sensitivity.

Prospective randomized contralateral eye evaluation of subjective quality of vision after wavefront-guided or wavefront- optimized photorefractive keratectomy

PURPOSE

To compare the effect of wavefront-guided (WFG) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) on patient perceived quality of vision.

METHODS

Seventy-one patients (142 eyes) were enrolled in this prospective, randomized, fellow eye controlled study. One eye was randomized to undergo WFG PRK treatment by the AMO Visx CustomVue S4 IR excimer laser system (Abbott Medical Optics, Inc., Santa Clara, CA) and the fellow eye received WFO PRK treatment by the Alcon Allegretto Wave Eye-Q 400 Hz excimer laser system (Alcon Laboratories, Inc., Fort Worth, TX). Patients answered questionnaires on their visual symptoms and quality of vision preoperatively and at 1, 3, 6, and 12 months after surgery.

RESULTS

Patients in both groups reported better vision compared to baseline from 3 months onward (mean change in score of 1.56 to 2.51 in the WFO group and 1.54 to 2.28 in the WFG group, P ⩽ .003). Both groups experienced less nighttime glare from 6 months onward (P ⩽ .030). Halos, double vision, and visual clarity were initially worse (P ⩽ .025) but not significantly different after 1 month. Haze and fluctuating vision resolved after 3 months. Visual symptoms were similar between the two groups at all times (P ⩾ .059) except at 6 months, when patients felt their WFG eyes had more excellent vision (P = .029). A composite of all symptoms was also similar between the groups until 12 months when patients had fewer symptoms in their WFO eye (P = .044).

CONCLUSIONS

One year after surgery, patient self-reported visual symptoms were not significantly different in eyes receiving WFG or WFO PRK. However, the average of all symptoms was lower in eyes receiving wavefront-optimized treatment.

Visual performance after conventional LASIK and wavefront-guided LASIK with iris-registration: results at 1 year

AIM

To compare visual performance of wavefront-guided laser in situ keratomileusis (LASIK) with iris-registration (Wg-LASIK group) and conventional LASIK (LASIK group) one year after surgery and analyze the correlation between wavefront aberrations and visual performance.

METHODS

Eight hundred and fifty-two myopic eyes of 430 patients were enrolled in this prospective study and divided into two groups: Wg-LASIK group (436 eyes) and LASIK group (416 eyes). A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square (RMS) of higher order aberrations, and Optec 6500 visual function instrument was used to measure contrast sensitivity (CS) before and 3, 6, 12 months after surgery.

RESULTS

The mean spherical equivalent (SE) in Wg-LASIK group was significantly better than those in LASIK group one year after surgery (P=0.024). Wg-LASIK eyes showed better CS values than LASIK eyes at all spatial frequencies with and without glare after surgery (P all<0.01). Moreover, the increase of higher RMS (RMSh), coma, RMS3, RMS4, RMS5 in Wg-LASIK group were significantly lower than those in LASIK group 1 year after surgery (P all<0.05). The increase of coma, spherical aberration (SA), RMS3 and RMS4 in Wg-LASIK and coma and RMS3 in LASIK group were negatively correlated with reduction of contrast sensitivity 1 year after surgery.

CONCLUSION

A significant better visual performance is got in Wg-LASIK group compared with LASIK group 1 year after surgery, and the Wg-LASIK is particularly suitable for eyes with high-magnitude RMSh.

One-year outcomes from a prospective, randomized, eye-to-eye comparison of wavefront-guided and wavefront-optimized LASIK in myopes

OBJECTIVE

To compare wavefront (WF)-guided and WF-optimized LASIK in myopes.

DESIGN

Prospective, randomized, eye-to-eye study.

PARTICIPANTS

A total of 72 eyes of 36 participants with myopia with or without astigmatism.

METHODS

Participants were randomized to receive WF-guided or WF-optimized LASIK with the WaveLight Allegretto Eye-Q 400-Hz excimer laser platform (Alcon, Inc., Hüenberg, Switzerland). LASIK flaps were created using the 150-kHz IntraLase iFS (Abbott Medical Optics, Santa Ana, CA). Evaluations included measurement of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), <5% and <25% contrast sensitivity, and WF aberrometry. Patients also completed a validated questionnaire detailing symptoms on a quantitative scale.

MAIN OUTCOME MEASURES

Safety, efficacy, predictability, refractive error, UDVA, CDVA, contrast sensitivity, and higher-order aberrations (HOAs).

RESULTS

The frequency with which the WF-guided and WF-optimized groups achieved postoperative UDVA of ≥ 20/16 or ≥ 20/20 and the frequency with which the groups lost 1 or 2 or more lines or maintained their preoperative CDVA were not statistically different from each other (all P > 0.05). The frequency with which the WF-guided group attained a refractive error within ± 0.25 diopters of emmetropia was higher than in the WF-optimized group (67.6%, 95% confidence interval [CI], 50.4-84.8 vs. 41.2%, 95% CI, 23.2-59.2; P = 0.03). The WF-guided group's mean UDVA was better than the WF-optimized group's UDVA by approximately 1 Early Treatment Diabetic Retinopathy Study line (-0.17 ± 0.11 logarithm of the minimum angle of resolution [logMAR], slightly <20/12 Snellen vs. -0.13 ± 0.12, slightly >20/16; P = 0.05). There were no statistically significant differences in contrast sensitivity, astigmatism, coma, or higher-order root mean square error between the groups (all P > 0.05), but the WF-guided group had less trefoil compared with the WF-optimized group (0.14 ± 0.07 vs. 0.20 ± 0.09; P < 0.01). There were no statistically significant differences in subjective parameters between the groups (all P > 0.05).

CONCLUSIONS

Wavefront-guided and WF-optimized LASIK using the Alcon WaveLight Allegretto Eye-Q 400-Hz excimer laser platform provide similar results in myopic patients; however, the WF-guided approach may yield small gains in visual acuity, predictability, and HOAs.

Wavefront-optimized excimer laser in situ keratomileusis for myopia and myopic astigmatism: refractive outcomes and corneal densitometry

PURPOSE

To determine the refractive outcomes of wavefront-optimized laser in situ keratomileusis (LASIK) treatments, in particular to measure corneal densitometry after LASIK using the densitometry function of the Pentacam Scheimpflug system.

SETTING

Division of Ophthalmology and Visual Sciences, University of Nottingham, United Kingdom.

DESIGN

Cohort study.

METHODS

Changes in postoperative visual acuity, refraction, and contrast sensitivity were evaluated after wavefront-optimized laser treatment. Corneal densitometry was evaluated with the Scheimpflug system before and after LASIK.

RESULTS

One year postoperatively, the uncorrected distance visual acuity was 6/6 or better in 92% of eyes and 6/9 or better in all eyes. Eighty-six percent of eyes had no change in the corrected distance visual acuity (CDVA); 4% gained 1 or more lines. Wavefront-optimized LASIK was stable over 1 year postoperatively. Eighty-nine percent of eyes were within ±0.50 diopter (D) and 100% were within ±1.00 D of the intended correction 1 year postoperatively. Contrast sensitivity showed a nonsignificant improvement (1.55 ± 0.10 [SD] preoperatively to 1.57 ± 0.09 12 months postoperatively) (P > .05). There was a nonsignificant increase in corneal densitometry 1 year postoperatively (from 12.72 ± 2.43 to 13.04 ± 2.58) (P > .05). No correlation was found between corneal densitometry and contrast sensitivity or CDVA.

CONCLUSIONS

Wavefront-optimized LASIK gave excellent refractive and visual outcomes and did not seem to affect corneal densitometry significantly 1 year postoperatively. However, larger studies may show a masked effect on corneal densitometry.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Meta-analysis of wavefront-guided vs. wavefront-optimized LASIK for myopia

PURPOSE

To detect possible differences in clinical outcomes between wavefront-guided laser in situ keratomileusis (LASIK) and wavefront-optimized LASIK for the treatment of myopia.

METHODS

A comprehensive literature search of Cochrane Library, MEDLINE, and EMBASE to identify relevant trials comparing LASIK with wavefront-guided and wavefront-optimized. A meta-analysis was performed on the results of the reports. Statistical analysis was performed using RevMan 5.0 software.

RESULTS

Seven articles describing a total of 930 eyes were identified. There were no statistically significant differences in the final proportion of eyes achieving uncorrected distance visual acuity of 20/20 or better [odds ratio, 1.04; 95% confidence interval (CI), 0.66 to 1.65; p = 0.86], manifest refractive spherical equivalent within ± 0.50 D of the target (odds ratio, 0.96; 95% CI, 0.53 to 1.75; p = 0.90). No patient lost ≥ 2 lines of distance-corrected visual acuity at posttreatment. The changes in higher order aberrations were not statistically significant different between the two groups with preoperative root-mean-square (RMS) higher order aberrations <0.3 μm (weighted mean difference, 0.01; 95% CI, -0.02 to 0.04; p = 0.57). However, wavefront-guided had a significant better postoperative aberration profile than wavefront-optimized with preoperative RMS higher order aberrations >0.3 μm (weighted mean difference, -0.10; 95% CI, -0.15 to -0.06; p < 0.00001).

CONCLUSIONS

Both wavefront-guided and wavefront-optimized LASIK have shown excellent efficacy, safety, and predictability. The wavefront-guided technology may be a more appropriate choice for patients who have preoperative RMS higher order aberrations >0.3 μm.

A prospective, randomized, fellow eye comparison of WaveLight® Allegretto Wave ® Eye-Q versus VISX CustomVue™ STAR S4 IR™ in laser in situ keratomileusis (LASIK): analysis of visual outcomes and higher order aberrations

Purpose

To compare outcomes in visual acuity, refractive error, higher-order aberrations (HOAs), contrast sensitivity, and dry eye in patients undergoing laser in situ keratomileusis (LASIK) using wavefront (WF) guided VISX CustomVue and WF optimized WaveLight Allegretto platforms.

Methods

In this randomized, prospective, single-masked, fellow eye study, LASIK was performed on 44 eyes (22 patients), with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Postoperative outcome measures at 3 months included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive error, root-mean-square (RMS) value of total and grouped HOAs, contrast sensitivity, and Schirmers testing.

Results

Mean values for UDVA (logMAR) were −0.067 ± 0.087 and −0.073 ± 0.092 in the WF optimized and WF guided groups, respectively (P = 0.909). UDVA of 20/20 or better was achieved in 91% of eyes undergoing LASIK with both lasers while UDVA of 20/15 or better was achieved in 64% of eyes using the Allegretto platform, and 59% of eyes using VISX CustomVue (P = 1.000). In the WF optimized group, total HOA increased 4% (P = 0.012), coma increased 11% (P = 0.065), and spherical aberration increased 19% (P = 0.214), while trefoil decreased 5% (P = 0.490). In the WF guided group, total HOA RMS decreased 9% (P = 0.126), coma decreased 18% (P = 0.144), spherical aberration decreased 27% (P = 0.713) and trefoil decreased 19% (P = 0.660). One patient lost one line of CDVA secondary to residual irregular astigmatism.

Conclusion

Both the WaveLight Allegretto and the VISX CustomVue platforms had equal visual and safety outcomes. Most wavefront optimized HOA values trended upward, with a statistically significant increase in total HOA RMS. Eyes treated with the WF guided platform showed a decreasing trend in HOA values.

Prospective, randomized, fellow eye comparison of WaveLight Allegretto Wave Eye-Q versus VISX CustomVueTM STAR S4 IRTM in photorefractive keratectomy: analysis of visual outcomes and higher-order aberrations

Background

The purpose of this study was to compare differences in visual outcomes, higher-order aberrations, contrast sensitivity, and dry eye in patients undergoing photorefractive keratectomy using wavefront-guided VISX CustomVue™ and wavefront-optimized WaveLight^® Allegretto platforms.

Methods

In this randomized, prospective, single-masked, fellow-eye study, photorefractive keratectomy was performed on 46 eyes from 23 patients, with one eye randomized to WaveLight Allegretto, and the fellow eye receiving VISX CustomVue. Three-month postoperative outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive error, root mean square of total and grouped higher-order aberrations, contrast sensitivity, and Schirmer’s testing.

Results

Mean values for uncorrected distance visual acuity (logMAR) were −0.03 ± 0.07 and −0.06 ± 0.09 in the wavefront-optimized and wavefront-guided groups, respectively (P = 0.121). Uncorrected distance visual acuity of 20/20 or better was achieved in 91% of eyes receiving wavefront-guided photorefractive keratectomy, and 87% of eyes receiving wavefront-optimized photorefractive keratectomy, whereas uncorrected distance visual acuity of 20/15 was achieved in 35% of the wavefront-optimized group and 64% of the wavefront-guided group (P ≥ 0.296). While root mean square of total higher-order aberration, coma, and trefoil tended to increase in the wavefront-optimized group (P = 0.091, P = 0.115, P = 0.459, respectively), only spherical aberration increased significantly (P = 0.014). Similar increases were found in wavefront- guided root mean square of total higher-order aberration (P = 0.113), coma (P = 0.403), trefoil (P = 0.603), and spherical aberration (P = 0.014). There was no significant difference in spherical aberration change when comparing the two platforms. The wavefront-guided group showed an increase in contrast sensitivity at 12 cycles per degree (P = 0.013).

Conclusion

Both VISX CustomVue and WaveLight Allegretto platforms performed equally in terms of visual acuity, safety, and predictability in photorefractive keratectomy. The wavefront-guided group showed slightly improved contrast sensitivity. Both lasers induced a comparable degree of statistically significant spherical aberration, and tended to increase other higher-order aberration measures as well.

A prospective, contralateral comparison of photorefractive keratectomy (PRK) versus thin-flap LASIK: assessment of visual function

Purpose:

To compare differences in visual acuity, contrast sensitivity, complications, and higher-order ocular aberrations (HOAs) in eyes with stable myopia undergoing either photo-refractive keratectomy (PRK) or thin-flap laser in situ keratomileusis (LASIK) (intended flap thickness of 90 μm) using the VISX Star S4 CustomVue excimer laser and the IntraLase FS60 femtosecond laser at 1, 3, and 6 months postoperatively.

Methods:

In this prospective, masked, and randomized pilot study, refractive surgery was performed contralaterally on 52 eyes: 26 with PRK and 26 with thin-flap LASIK. Primary outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), contrast sensitivity, and complications.

Results:

At 6 months, mean values for UDVA (logMAR) were −0.043 ± 0.668 and −0.061 ± 0.099 in the PRK and thin-flap LASIK groups, respectively (n = 25, P = 0.466). UDVA of 20/20 or better was achieved in 96% of eyes undergoing PRK and 92% of eyes undergoing thin-flap LASIK, whereas 20/15 vision or better was achieved in 73% of eyes undergoing PRK and 72% of eyes undergoing thin-flap LASIK (P > 0.600). Significant differences were not found between treatment groups in contrast sensitivity (P ≥ 0.156) or CDVA (P = 0.800) at postoperative 6 months. Types of complications differed between groups, notably 35% of eyes in the thin-flap LASIK group experiencing complications, including microstriae and 2 flap tears.

Conclusion:

Under well-controlled surgical conditions, PRK and thin-flap LASIK refractive surgeries achieve similar results in visual acuity, contrast sensitivity, and induction of HOAs, with differences in experienced complications.