Wavefront-guided LASIK Research Articles

Contrast Sensitivity and Stereopsis Outcomes Following LASIK Presbyopia Correction Based on the Corneal Aberration Modulation or Corneal Multifocality Induction Methods: A Systematic Review

Background. Modern laser vision correction for presbyopia treatment involves non-linear aspheric corneal ablation with the controlled induction of spherical aberration modulation to extend the depth of focus or corneal multifocality induction methods with or without micro-monovision in the non-dominant eye to provide continuous clear vision across distances. Anisometropia and the new higher-order aberrations pattern may be potential risk factors for postoperative stereopsis and contrast sensitivity (CS) deterioration. Purpose. The objective of this systematic review was to assess articles published until 2023 in which CS and/or stereopsis were reported following LASIK presbyopia treatment. Methods. We searched the PubMed, Scopus and Web of Science databases in accordance with the PRISMA 2020 flow diagram. The inclusion criteria specified original papers evaluating the outcomes of laser presbyopia correction as well as the pre- and postoperative assessment of stereopsis and/or CS. The Quality Assessment Tool was applied to assess the risk of bias. Results. We identified 13 studies, including 856 presbyopes (1712 eyes), with preoperative refractive errors from −11.13 D to +5.75 D, with the follow-up range between 3 and 30 months. Either contrast sensitivity improvement or no change following Presbyond® Laser Blended Vision and PresbyMAX® Hybrid was found in the reviewed articles. Some authors reported a significant CS reduction after symmetrical PresbyLASIK, wavefront-guided LASIK and aspheric monovision LASIK. Several studies assessing the effect of Presbyond® LBV on stereopsis showed conflicting results, with the near stereopsis being reduced, unchanged or increased. A significant decrease in stereopsis was reported after aspheric monovision LASIK. (5) Conclusions. The Presbyond® Laser Blended Vision is a safe procedure in terms of the preservation of contrast sensitivity for presbyopia treatment. More studies are needed to elucidate the impact of aspheric corneal ablation methods or other methods inducing corneal multifocality with or without micro-monovision on stereopsis and contrast sensitivity.

Recent Advances in Refractive Surgery: An Overview.

Refractive surgery has experienced substantial advancements over the past few years, driven by innovative techniques and continuous technological progress aimed at enhancing visual outcomes and patient satisfaction. Refractive errors such as myopia, hyperopia, and astigmatism affect a significant portion of the global population, impacting quality of life and productivity. Recent advancements have been fueled by a deeper understanding of ocular biomechanics and visual optics, leading to more precise and effective treatments. Traditional methods such as LASIK and PRK have been refined, and new procedures like SMILE (Small Incision Lenticule Extraction) have been introduced, expanding the range of treatable refractive errors and improving safety and predictability. Customized treatments, such as wavefront-guided LASIK and topography-guided PRK, allow for individualized plans tailored to each patient's unique corneal characteristics, enhancing visual acuity and reducing higher-order aberrations. The use of femtosecond lasers in procedures like Femto-LASIK and femtosecond laser-assisted cataract surgery (FLACS) offers unparalleled precision, reducing surgical risks and improving outcomes. Implantable Collamer Lenses (ICLs) and corneal crosslinking (CXL) have emerged as effective options for specific patient groups. Advanced diagnostic tools like optical coherence tomography (OCT) and Scheimpflug imaging have improved surgical planning and complication management. As research and technology continue to evolve, these advancements promise even greater improvements in refractive surgery, addressing the visual needs of the global population.

Comparison of visual quality after wavefront-guided LASIK in patients with different levels of preoperative total ocular higher-order aberrations: a retrospective study.

To compare the visual quality after wavefront-guided femtosecond LASIK (WFG FS-LASIK) in patients with different levels of preoperative total ocular higher-order aberrations to guide clinical decision-making regarding patient selection and treatment strategies. This study included 112 right eyes of 112 patients who previously underwent WFG FS-LASIK for correcting myopia and myopic astigmatism. The patients were divided into two groups based on the mean values of preoperative total ocular HOAs (0.30 ± 0.09 µm): HOA ≤ 0.3 and > 0.3 groups. The visual acuity, manifest refraction, corneal Strehl ratio (SR), root mean square (RMS) of corneal and ocular aberrations, and area under the log contrast sensitivity function (AULCSF) of both groups were compared preoperatively and at 1, 3, 6, and 12 months postoperatively. The induced ocular HOAs and coma (Δ = 1 mo - Preop) were significantly lower in the HOAs > 0.3 group than in the HOAs ≤ 0.3 group (ΔHOAs: 0.39 ± 0.19 vs. 0.29 ± 0.18 μm, t = 2.797, P = 0.006; Δ coma: 0.30 ± 0.19 vs. 0.20 ± 0.21 μm, t = 2.542, P = 0.012). In the HOAs > 0.3 group, ΔHOAs were negatively correlated with the preoperative ocular HOAs (r = -0.315, P = 0.019). In the HOAs ≤ 0.3 group, the regression equation for Δ HOAs = 0.098 + 0.053 |SE| (F = 21.756, P < 0.001). In the HOAs > 0.3 group, the regression equation for ΔHOAs = 0.534 - 1.081 HOAs + 0.038|Sphere| (F = 7.954, P = 0.001). The postoperative uncorrected distance visual acuity, spherical equivalent, corneal aberrations, SR and AULCSF of both groups were similar (all P > 0.05). Furthermore, the ocular aberrations were not significantly different between both groups at 3, 6, and 12 months postoperatively (all P > 0.05). In addition, compared with the preoperative period, the AULCSF of both groups were significantly increased in the postoperative period (all P < 0.05). The induced ocular HOAs and coma in HOAs > 0.3 group were lower. However, both groups achieved equivalent and excellent visual quality after WFG FS-LASIK. WFG FS-LASIK may provide significant visual benefits for a wider range of patients.

Clinical outcomes and higher order aberrations of wavefront-guided LASIK versus SMILE for correction of myopia: A systemic review and meta-analysis.

To systematically evaluate the clinical effect of wavefront-guided laser in situ keratomileusis (WFG-LASIK) and small incision lenticule extraction (SMILE) in terms of refractive errors and high-order aberrations. A systematic literature search of PubMed, EMBASE, the Cochrane Library, Web of Science and China National Knowledge Internet was performed to identify studies evaluating the clinical outcomes of SMILE and WFG-LASIK ended in May 2022. Meta-analyses were performed according to the PRISMA guidelines. The risk of bias of the RCTs was evaluated using the Cochrane Handbook criteria, and the quality of the non-randomised controlled studies was assessed using the Newcastle-Ottawa Scale. In total, 1385 eyes (SMILE group, 750 eyes; WFG-LASIK group, 635 eyes) from 12 studies were included. The meta-analysis demonstrated that spherical aberration was smaller in the SMILE group than in the WFG-LASIK group (standardised mean difference [SMD]: -0.34, 95% confidence interval [CI]: -0.47, -0.22; p< 0.00001), and that the postoperative values of vertical coma (SMD: 0.83; 95% CI: 0.63, 1.03; p< 0.00001) and trefoil (SMD: 0.37; 95% CI: 0.02, 0.72; p=0.04) were higher in the SMILE group compared to the WFG LASIK group. There were no significant differences in the clinical outcomes and the values of induced total higher order aberrations between the WFG-LASIK and SMILE groups (SMD: 0.05; 95% CI: -0.09, 0.19; p=0.47). Both SMILE and WFG-LASIK were found to be safe, effective, and predictable. SMILE may induce more vertical coma and trefoil, whereas WFG LASIK may induce more spherical aberrations, but no significant differences were found in the total higher order aberrations between SMILE and WFG-LASIK.

Сравнение результатов коррекции миопии с помощью visx customvue wavefront-guided lasik и стандартным lasik

Purpose. To compare visual and clinical outcomes of wavefront-guided VISX CustomVue (VISX, Santa Clara, CA) LASIK and conventional LASIK. Methods. This study retrospectively evaluated 130 eyes of 65 patients, including 40 eyes of 20 patients in the CustomVue group and 90 eyes of 45 patients in conventional LASIK group. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, and refractive error were measured. Higher-order aberration (HOA) were measured by WaveScan system using a Hartmann-Shack sensor as their root mean square values (RMS HO), and individual Zernike coefficients of 3rd to 4th order before and 1 year after the surgery and compared using Mann-Whitney test or Student's t-test. Results. There was no significant difference in spherical equivalent between the groups. CV eyes showed superiority in number of eyes seeing 20/20 or better. RMS HO was less in CV group than that induced by conventional LASIK (0.37 ± 0.15 µm and 0.62 ± 0.26 µm, respectively). Preoperative mean RMS HO more than 0.3 µm was associated with a decrease in postoperative HOA in CV group. CV system induced significantly less spherical aberration (0.149 ± 0.157 µm and 0.364 ± 0.284 µm, respectively, р &lt; 0,002). Conclusions. CustomVue seems to have better uncorrected visual acuity outcomes. It generally increases HOA, but statistically significant by less, compared with conventional LASIK. The most benefits have patients with RMS HO higher than 03 µm. Key words: CustomVue, conventional LASIK, wavefront-guided LASIK.

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

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. 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. 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. 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.

Wave front aberrations induced from biomechanical effects after customized myopic laser refractive surgery in finite element model.

A customized myopic refractive surgery was simulated by establishing a finite element model of the human eye, after which we studied the wave front aberrations induced by biomechanical effects and ablation profile after wave front-guided LASIK surgery. Thirty myopia patients (i.e., 60 eyes) without other eye diseases were selected. Their ages, preoperative spherical equivalent, astigmatism, and wave front aberration were then obtained, in addition to the mean spherical equivalent error range - 4 to - 8D. Afterward, wave front-guided customized LASIK surgery was simulated by establishing a finite element eye model, followed by the analysis of the wave front aberrations induced by the surface displacement from corneal biomechanical effects, as well as customized ablation profile. Finally, the preoperative and induced aberrations were statistically analyzed. Comatic aberrations were the main wave front abnormality induced by biomechanical effects, and the wave front aberrations induced by the ablation profile mainly included coma and secondary coma, as well as sphere and secondary-sphere aberrations. Overall, the total high-order aberrations (tHOAs), total coma (C31), and sphere ([Formula: see text]) increased after wave front-guided customized LASIK surgery. According to our correlation analyses, coma, sphere, and tHOAs were significantly correlated with decentration. Additionally, the material parameters of ocular tissue were found to affect the postoperative wave front aberrations. When the material parameters of the sclera remained constant but those of cornea increased, the induced wave front aberrations were reduced. All biomechanical effects of cornea and ablation profile had significant effects on postoperative wave front aberrations after customized LASIK refractive surgery; however, the effects of the ablation profile were more notorious. Additionally, the characteristics of biomechanical materials have influence on the clinical correction effect.

Comparison of Wavefront-Guided Femtosecond LASIK and Optimized SMILE for Correction of Moderate-to-High Astigmatism.

To compare refractive outcomes, higher order aberrations (HOAs), and the changes in contrast sensitivity after wavefront-guided femtosecond laser-assisted in situ keratomileusis (WFG LASIK) and optimized small incision lenticule extraction (SMILE) for moderate-to-high astigmatism correction. This prospective, randomized study included 87 eyes: 40 eyes in the WFG LASIK group and 47 eyes in the SMILE group. Manual cyclotorsion compensation by marking the horizontal axis before SMILE surgery was used for optimized SMILE. Refractive diopter, aberrations, and contrast sensitivity were assessed 3 months postoperatively. The Alpins vector analysis method was used to analyze the astigmatic changes after surgery. There were no significant differences in the corrected distance visual acuity and refraction between the two groups after surgery. The fitted curve of surgically induced astigmatism versus target induced astigmatism was described as y = 0.9905 x + 0.0009 in the WFG LASIK group and y = 0.9672 x + 0.0026 in the SMILE group. The percentage of corneal astigmatism axis change within 5 degrees was statistically significant (chi-square test: 10.632, P = .001). HOAs increased in both the WFG LASIK and SMILE groups after surgery (t = -3.655, P = .001, t = -3.784, P = .001, respectively). However, comparison of the changes of HOAs between both groups was not significant (t = -0.565, P = .575). The improvement in contrast sensitivity in the WFG LASIK group was significantly higher than that in the SMILE group. WFG LASIK and optimized SMILE can achieve similar outcomes for astigmatism correction. Optimized SMILE with marking could achieve good astigmatism correction, even without an eye tracking system. [J Refract Surg. 2021;37(3):166-173.].

Wavefront-guided and Wavefront-optimized LASIK: Visual and Military Task Performance Outcomes.

Wavefront-guided and Wavefront-optimized LASIK: Visual and Military Task Performance Outcomes.

A Prospective Comparison of Wavefront-Guided LASIK versus Wavefront-Guided PRK After Previous Keratorefractive Surgery.

PurposeTo compare the results of retreatment with wavefront-guided LASIK versus wavefront-guided PRK for residual refractive error following previous myopic keratorefractive surgery.MethodsIn this prospective study, 32 eyes of 28 patients after prior myopic keratorefractive surgery underwent retreatment with flap-lift wavefront-guided LASIK (n = 12) or wavefront-guided PRK (n = 20) for residual refractive error. Safety, efficacy, predictability, and wavefront outcomes were evaluated.ResultsAt last follow-up, both LASIK and PRK retreatment resulted in similar improvement in visual acuity with respective mean ± standard deviation (SD) uncorrected distance visual acuity of −0.07 ± 0.11 logMAR and −0.06 ± 0.13 logMAR (p = 0.87). In the study, 16.7% of LASIK and 33.3% of PRK eyes gained one or more lines of best-corrected distance visual acuity (CDVA), while 16.7% and 9.5% of eyes lost one or more lines of CDVA with LASIK and PRK, respectively. One hundred % of LASIK eyes and 89.5% of PRK eyes were within ± 0.50 diopters of emmetropia. Wavefront analysis demonstrated similar reductions in total RMS error higher-order aberrations (p = 0.84) with no difference in coma, trefoil, or spherical aberration between eyes undergoing LASIK or PRK retreatment.ConclusionWavefront-guided LASIK and wavefront-guided PRK following previous keratorefractive surgery demonstrate similar safety, efficacy, and predictability with comparable wavefront outcomes.

Comparison of the visual quality at 1 year following femtosecond laser-assisted LASIK, wavefront-guided femtosecond LASIK and small incision lenticule extraction for myopia and astigmatism

Objective: To investigate mesopic contrast sensitivity (CS) and high-order aberrations after femtosecond laser-assisted LASIK (FS-LASIK), wavefront-guided femtosecond LASIK (WF-LASIK) and small incision lenticule extraction (SMILE) for myopia and astigmatism. Methods: In this case-control study, 212 eyes of 108 patients with myopia and astigmatism from September 2014 to September 2016 were treated by refractive surgery. There were 34 males (66 eyes) and 74 females (146 = eyes), aged 27 (24, 32) years. They were divided into 3 groups, with 37 patients (71 eyes), 35 patients (69 eyes) and 36 patients (72 eyes) treated by FS-LASIK, WF-LASIK and SMILE, respectively. Refraction diopters, corneal tomography, wavefront aberrations and contrast sensitivity were evaluated before and at 12 months after surgery. The results of different groups were compared by rank sum test. Results: At 12 = months of follow-up, 69 eyes (97.18%) treated by FS-LASIK, 67 eyes (97.10%) by WF-LASIK and 69 eyes (95.83%) by SMILE had the uncorrected distance visual acuity of 20/20 or better. Fifty-nine eyes (83.10%) treated by FS-LASIK, 60 eyes (86.96%) by WF-LASIK and 61 eyes (84.72%) by SMILE had better postoperative uncorrected distance visual acuity than preoperative corrected distance visual acuity. Surface regularity index of the WF-LASIK group decreased from 0.11 (0.07, 0.28) to 0.07 (0.06, 0.20) (Z=-2.662, P=0.008), which was less than that of the FS-LASIK and SMILE groups (Z=-3.236, -3.118, P=0.001, 0.000). Surface asymmetry index of the WF-LASIK group increased from 0.34 (0.25, 0.43) to 0.38 (0.30, 0.52) (Z=-2.140, P=0.032), which was less than that of the FS-LASIK and SMILE groups (Z=-2.910, -3.779, P=0.004, 0.000). The root mean square of high-order of the FS-LASIK group increased from 0.32 (0.27, 0.41) to 0.53 (0.40, 0.65) (Z=-6.228, P=0.000), which was more than that of the WF-LASIK and SMILE groups (Z=-3.595, -4.806, P=0.000, 0.000). Coma of the WF-LASIK group increased from 0.16 (0.11, 0.24) to 0.26 (0.15, 0.37) (Z=-3.816, P=0.000), which was less than that of the FS-LASIK group (Z=-3.528, P=0.000). Spherical aberration of the FS-LASIK and WF-LASIK groups increased from 0.10 (0.05, 0.21) and 0.08 (0.04, 0.12) to 0.24 (0.13, 0.34) and 0.15 (0.09, 0.26), respectively (Z=-5.141, -4.864, P=0.000, 0.000), which were more than that of the SMILE group (Z=-2.549, -4.682, P=0.011, 0.000). CS of the WF-LASIK group at 12 cycles per degree (c/d) increased from 1.34 (1.18, 1.48) to 1.48 (1.34, 1.63) (Z=-2.985, P=0.003), which was more than that of the FS-LASIK and SMILE groups (Z=-3.194, -2.977, P=0.001, 0.003). CS with glare of the WF-LASIK group at 12.0 c/d increased from 1.26 (1.18, 1.34) to 1.34 (1.34, 1.63) (Z=-3.608, P=0.000), which was more than that of the FS-LASIK and SMILE groups (Z=-4.033, -2.913, P=0.000, 0.004). Conclusions: FS-LASIK, WF-LASIK and SMILE achieved ideal visual outcomes at 12 months postoperatively. WF-LASIK treated eyes showed the best corneal symmetry, the least increase of high-order aberrations and the best visual quality among three kinds of surgeries. (Chin J Ophthalmol, 2020, 56: 118-125).

Astigmatic Outcomes after Wavefront-Guided and Wavefront-Optimized Refractive Surgeries for Myopia with Low to Moderate Cylinder

Purpose: To compare the efficacy and accuracy of wavefront-guided (WFG) and wavefront-optimized (WFO) PRK and LASIK for the treatment of myopia with low to moderate astigmatism.Methods: In this prospective cohort study, 215 active duty military service members (430 eyes, mean spherical equivalent -3.61 ± 1.53 D) electing either PRK or LASIK were randomized to undergo WFG or WFO treatment. Up to 12 months, postoperative visual outcomes following surgeries were compared between 4 treatment groups: WFG PRK, WFG LASIK, WFO PRK, and WFO LASIK for myopia with 0.25 to 0.50 D astigmatism (≤ 0.50 D cyl subgroup) and ≥ 0.75 D astigmatism (≥ 0.75 D cyl subgroup). High and low contrast visual acuities were assessed and vector analysis was performed.Results: At 12 months postoperatively, the surgically induced astigmatism, magnitude of error, correction and flattening indices were significantly different between treatment groups (P values ≤ 0.001) in the ≤ 0.50 D cyl subgroup. In ≥ the 0.75 D cyl subgroup, there were no significant differences in vector analysis parameters except for the magnitude of error and correction index (P values ≤ 0.010). The treatment groups were comparable in terms of postoperative uncorrected distance visual acuity, manifest spherical equivalent, and best-corrected low contrast visual acuity.Conclusions: No treatment modality showed consistent superiority in correcting low to moderate astigmatism. Overall, both PRK and LASIK using either wavefront-guided or wavefront-optimized laser platforms were similarly effective and accurate in treating myopia with a low to moderate amount of astigmatism.

Wavefront-guided LASIK for Monovision Treatment of Myopic Subjects With Presbyopia

Wavefront-guided LASIK for Monovision Treatment of Myopic Subjects With Presbyopia

Evaluation of Clinical Outcomes after LASIK for the Correction of Myopia Using the Advanced Customvue Excimer Laser Platform

-Purpose: To evaluate early visual, refractive and aberrometric outcomes after wave front-guided LASIK for the correction of low to moderate myopia and myopic astigmat is musing the excimer laser platform Advanced Custom Vue. Methods: A prospective, non-comparative study in 100 myopic eyes of 50 patients evaluating LASIK results over a period of 3 months. Main outcome variables included visual acuity, refraction, total higher-order aberrations (HOAs), spherical aberration (SA) and coma-like aberration. The surgery was performed using the VISX STAR S4 (Johnson and Johnson Vision) excimer laser and a wave front-guided ablation designed according to the iDesign aberrometer data (Johnson and Johnson Vision). Results: Mean preoperative sphere decreased from -4.07 ± 1.78 D to 0.32 ± 0.30 D at 3 months after surgery. Mean preoperative cylinder was reduced from -1.09 ± 0.88 D to -0.26 ± 0.28 D after the complete follow-up. Postoperative uncorrected distance visual acuity (UDVA) was 0.00 logMAR (20/20) or better in 100% of eyes, and 65.3% of eyes reached an UDVA of -0.20 logMAR (20/12.5) or better (p < 0.05). For a 6-mm pupil, the root mean square (RMS) for total ocular HOAs increased with surgery by 0.03 μm (p = 0.050), whereas the coma-like RMS increased by 0.05 μm (p < 0.001). The change in spherical aberration was +0.08 μm (p < 0.001). Conclusion: Wavefront-guided LASIK using the new generation excimer laser platform Advanced Custom Vue is safe and effective for treating myopia and myopic astigmatism, minimizing the postoperative level of HOAs.

Comparative Analysis of the Clinical Outcomes of SMILE and Wavefront-Guided LASIK in Low and Moderate Myopia.

To compare the clinical outcomes of small incision lenticule extraction (SMILE) and wavefront-guided LASIK (WFG LASIK) in eyes with low and moderate myopia. This was a prospective, comparative study enrolling 110 eyes with low and moderate myopia (spherical equivalent ≤ 6.00 diopters [D]). Two groups were differentiated according to the surgical technique used: the WFG LASIK group included 51 eyes (51 patients) undergoing WFG LASIK using the STAR S4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Abbott Park, IL) and the SMILE group included 59 eyes (59 patients) undergoing SMILE with the VisuMax platform (Carl Zeiss Meditec, Jena, Germany). Visual, refractive, aberrometric, and contrast sensitivity outcomes were evaluated during a 6-month follow-up. Mean efficacy index was 0.92 ± 0.11 and 1.12 ± 0.17 in the SMILE and WFG LASIK groups, respectively (P < .001). Postoperative spherical equivalent was within ±0.50 D in 81.54% and 98% of eyes in the SMILE and WFG LASIK groups (P < .001), and postoperative cylinder was 0.50 or below in 84.7% and 100% of eyes, respectively (P = .038). Mean safety index was 0.98 ± 0.08 and 1.20 ± 0.14 in the SMILE and WFG LASIK groups (P < .001), with losses of lines of corrected distance visual acuity in 6.8% and 0.0% of eyes, respectively. Higher increase in higher order (P < .001) and coma (P < .001) root mean square and higher decrease in contrast sensitivity for 6, 12, and 18 cycles/degree (P ≤ .001) were observed after SMILE. SMILE and WFG LASIK are efficacious and safe procedures for the correction of low and moderate myopia, but WFG LASIK allows a more predictable outcome and better aberrometric control. [J Refract Surg. 2017;33(5):298-304.].

Subjective Quality of Vision After Myopic LASIK: Prospective 1-Year Comparison of Two Wavefront-Guided Excimer Lasers

To compare subjective quality of vision between two wavefront-guided lasers in the treatment of myopia up to 1 year postoperatively. In this prospective randomized study, 100 eyes of 50 patients were treated with wavefront-guided LASIK. One eye was treated with the WaveLight Allegretto Wave Eye-Q 400-Hz excimer laser (Alcon Laboratories, Inc., Hünenberg, Switzerland) and the other was treated with the VISX Star S4 IR CustomVue excimer laser (Abbott Medical Optics, Santa Ana, CA). Patients completed a questionnaire assessing quality of vision and visual symptoms preoperatively and at postoperative months 1, 3, 6, and 12. The Allegretto system demonstrated non-statistically significant superiority in several subjective parameters as early as 1 month after surgery. At 12 months, there was better clarity during the day (P = .001) in the Allegretto group. Subgroup analyses were performed on eyes with preoperative higher order aberrations of 0.3 µm or less and in patients with preoperative higher order aberrations greater than 0.3 µm. In subgroup analysis, there were no differences between the two systems in eyes with low higher order aberrations or high higher order aberrations. Patients did not express any preference for one system over the other when surveyed at 1 year postoperatively. One year after surgery, there were no differences in self-reported quality of vision outcomes with the exception of better clarity of vision during the day in the eyes treated with the Allegretto system. Patients did not express any preference for one treatment modality over the other.

Femtosecond Laser-assisted Wavefront-guided LASIK Using a Newer Generation Aberrometer: 1-Year Results.

To evaluate long-term outcomes of wavefront-guided LASIK with a new advanced aberrometer. Fifty eyes of 25 LASIK candidates with myopia and/or astigmatism underwent aberrometry (iDesign Advanced WaveScan; Abbott Medical Optics, Santa Ana, CA), femtosecond laser-assisted flap creation, and excimer ablation. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SEQ), and astigmatism outcomes were measured at 1, 3, 6, and 12 months postoperatively. The sphere, cylinder, and SEQ were -4.29 ± 1.94, -0.75 ± 0.76, and -4.67 ± 2.01 diopters (D), respectively, preoperatively and 0.03 ± 0.13, -0.09 ± 0.13, and -0.02 ± 0.14 D, respectively, 12 months postoperatively (P < .001). The postoperative log-MAR CDVA (-0.07 ± 0.09) and UDVA (-0.04 ± 0.09) were better than the preoperative logMAR CDVA (0.07 ± 0.10) (P < .01). Ninety-four percent achieved a 12-month logMAR UDVA of 0.0 or less (20/20 or better Snellen) and 100% achieved 0.3 or less (20/40 or better Snellen), compared to a preoperative logMAR CDVA of 0.0 or worse in 54% and 0.3 or less in 100%. Postoperative SEQ was within ±0.50 D in 98%. The regression plot for achieved (y) vs intended (x) correction at 12 months was (y = 0.98 × - 0.09, R(2) = 0.99, P < .001). No cases lost CDVA. The target and 12-month surgically induced astigmatisms (TIA and SIA) were 0.91 ± 0.75 and 0.82 ± 0.70, respectively. The regression plot between them was SIA = 0.91 × TIA - 0.01 (R(2) = 0.95, P < .001). The angle of error was -0.29° ± 12.6° and index of success was 0.13 ± 0.25. There was only a mild, nonsignificant increase of higher-order aberrations after surgery, and the postoperative wavefront was stable on follow-up. Wavefront-guided LASIK with iDesign aberrometry appears to be safe and effective in this long-term, consecutive case series.

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study.

To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

Day 1 wavefront aberrometry for prediction of refractive outcomes at year 1 in myopic LASIK.

To determine amount of change in wavefront aberrometric measurements from 1 day to 1 year after myopic LASIK. One hundred five eyes of 105 patients underwent wavefront-guided LASIK. Objective wavefront aberrometric refractions were recorded preoperatively, at postoperative day 1, and at postoperative year 1. Subjective manifest refractions were also collected at postoperative year 1. When comparing objective wavefront aberrometric refractions at postoperative year 1 to postoperative day 1, there was a mean 0.33 diopter spherical equivalent myopic shift. There was no significant difference in the number of eyes within 1.00 diopter of emmetropia spherical equivalent measured by wavefront aberrometric refraction at postoperative day 1 or year 1. There was a correlation of R(2) = 0.14 between degree of preoperative myopia and myopic shift. Higher-order aberrations were overall not increased at day 1 but increased significantly by year 1. Objective aberrometric refractions at postoperative day 1 can be useful in prediction of long-term refractive outcomes. There is a small myopic shift and an increase in higher-order aberrations when comparing wavefront aberrometry results at postoperative day 1 with those at postoperative 1 year.

Refractive outcome of wavefront guided laser in situ keratomileusis and wavefront guided photorefractive keratectomy in high pre-existing higher order aberration.

To compare visual outcome and higher order aberrations (HOA) between wavefront-guided LASIK (WF-LASIK) and wavefront guided PRK (WF-PRK) in patients with high preoperative HOA. Randomized prospective interventional study. Conducted at Guru Nanak Eye Centre, Maulana Azad Medical College, Delhi, India. Eighty myopic eyes of forty patients were included. age more than 21 years, best corrected visual acuity of 20/20 or better, a stable refraction, to be off soft contact lens for minimum 14 days prior to preoperative examination, preoperative RMS HOA more than 0.35 μ, preoperative central corneal thickness at least 500 μm, estimated residual stromal bed thickness of at least 275 μm in patients undergoing WF-LASIK and 350 μm in patients undergoing WF-PRK. Exclusion criteria were severe dry eye, blepharitis, corneal disease and warpage, uveitis, posterior segment abnormalities involving the macula or optic nerve and systemic diseases. Patients were randomly divided into two groups. They underwent either WF-LASIK (group A) or WF-PRK (group B) over 2 years (40 eyes each). Patients were followed up for 6 months. Main outcome measures were efficacy, safety, stability, predictability and HOA. At 6 months mean uncorrected visual acuity (logMAR) in group A was -0.01 ± 0.04 and group B was 0.00 ± 0.07 (P = 0.23). HOA RMS (6mm pupil) in group A was 0.61 ± 0.24 μm and group B was 0.55 ± 0.25 μm. The increase was statistically significant in both the groups (P < 0.05). Both the groups showed similar efficacy, predictability and safety. WF-LASIK and WF-PRK have similar efficacy, safety and predictability, though WF-PRK induces less HOA.