Schwind Amaris Research Articles

Prospective Objective Analysis of Corneal Haze Following Customized Transepithelial PRK Without Mitomycin C Combined With Accelerated Corneal Cross-Linking Versus Corneal Cross-Linking Alone.

To compare haze and refractive outcomes in patients undergoing combined accelerated corneal cross-linking (A-CXL) and selective wavefront-guided transepithelial photorefractive keratectomy (WG-transPRK) without mitomycin C (MMC) versus those undergoing A-CXL. This prospective study analyzed 95 eyes (86 patients) with progressive keratoconus from October 2018 to October 2022. The first group underwent CXL combined with corneal or ocular WG-transPRK (CXL+PRK, n = 52), targeting higher order aberrations (HOAs). The second underwent CXL only (n = 43), both following the same accelerated CXL protocol without MMC on the SCHWIND Amaris laser platform (SCHWIND eye-tech-solutions). Baseline and postoperative evaluations (1, 3, 6, and 12 months) included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, tomography, corneal HOAs, and optical coherence tomography (OCT) scans. A patented machine learning algorithm objectively detected and quantified stromal haze on OCT scans in grayscale units. In both groups, anterior corneal haze reflectivity and subepithelial haze peaked at 3 months postoperatively, then progressively decreased at 6 and 12 months. Haze did not differ between groups at any time point. By 12 months, CDVA increased by 2.5 lines in the CXL+PRK group (P < .001) and by 0.7 lines in the CXL group (P = .10), and maximum keratometry decreased from 51.70 ± 5.10 to 47.90 ± 7.90 diopters (D) (CXL+PRK group) (P < .001) and from 51.20 ± 5.10 to 50.30 ± 4.60 D (CXL group) (P = .004). Corneal HOAs decreased in both groups but more in the CXL+PRK group. Combining CXL with WG-transPRK without MMC does not result in increased haze when compared to A-CXL alone. This combined approach achieves greater improvements in visual, topographic, and aberrometric parameters. [J Refract Surg. 2024;40(9):e583-e594.].

Solid-state laser (266 nm) as an alternative to ArF excimer laser (193 nm) for corneal reshaping: Comparative numerical study of the thermal effect.

Laser corneal reshaping is a safe and effective technique utilized to treat common vision disorders. An advanced laser delivery system equipped with a pulsed UV laser with specific parameters is used to ablate parts of the cornea surface to correct the existing refractive error. The argon fluoride (ArF) excimer pulsed gas laser at 193 nm is the most employed type in the commercial devices for such treatments. This laser is generated using a mixture of Argon, Fluorine, and a significant amount of Neon gases. However, due to the ongoing Russian-Ukraine war, the availability of Neon gas is currently very limited, as this region is considered the primary supplier of pure Neon gas. Consequently we suggest replacing the common ArF laser source in the commercial devices with a solid-state (forth harmonic neodymium-doped yttrium aluminum garnet laser at 266 nm). This replacement uses the same operation parameters, optics, and scanning algorithm. Parameters from five commercial devices (Zeiss MEL 90, Technolas TENEO 317, Alcon Wave Light EX 500, Schwind Amaris 750 s, OptoSystems MICROSCAN VISUM) were compared with those of the i-ablation device, a research device that uses a 266 nm laser source. Our goal is to reduce production costs through a simple modification that has a significant impact. Consequently, the present study aims to find an alternative laser source for the current ArF laser without exchanging the complete system's design. This recommendation is based on a numerical simulation study. The thermal effect on a human cornea model was numerically evaluated using finite-element solutions of Pennes' bioheat equation on the COMSOL platform by applying two laser wavelengths. The results demonstrated that changing the laser source significantly impacts the thermal effect, even with the same laser settings. All studied devices showed a reduction in the thermal effect to below 40°C, compared with nearly 100°C under ordinary conditions.

A comparison of the results of old-generation (MEL 60) and new-generation (SCHWIND AMARIS) refractive excimer laser treatments

AbstractPurposeThe present study compares the efficacy of refractive surgery using third-generation and sixth-generation laser vision correction procedures in terms of postoperative visual acuity. The goal of the authors was to determine whether advances in laser technology had improved patients' uncorrected visual acuity, as measured at six-month follow-ups.Materials/MethodsResults were reported from one of Europe's leading laser eye clinics, which has performed an outstandingly high number of treatments (over 100,000). The results of the clinic's first 10,000 treatments and most recent 10,000 treatments were evaluated.ResultsThe analysis was performed by treated dioptric range and age group. The raw six-month visual acuity results show a statistically significant improvement over the last 10,000 interventions. The treatments resulted in significant improvements in all groups compared to the previous technology. With the new devices, visual acuity increased to above 1.0 in young myopes. The best results were seen in patients between 18 and 45 years of age, in the dioptric range between −1.0 D and −6.0 D.ConclusionsIt can be concluded that advances in technology improved refractive outcomes in all patient groups. This conclusion has excellent reliability and predictability due to the particularly high number of cases.

Effect of Astigmatism Treatment With Three Excimer Lasers After Photorefractive Keratectomy.

To compare astigmatism correction after photorefractive keratectomy (PRK) using three excimer laser devices, Alcon Wavelight EX500, Schwind Amaris 1,050, and Technolas Teneo317 M2. This retrospective study included 414 eyes from 414 subjects with a history of PRK performed using Alcon Wavelight (n=172), Schwind Amaris (n=122), and Technolas (n=120). Uncorrected & corrected distance visual acuity (UDVA & CDVA), and refractive status (spherical equivalent (SE) and vector analysis (J0 and J45)) were postoperatively recorded at the 6-month and 12-month examinations. The mean CDVA and J45 at 6-month and 12-month showed no statistically significant difference among the three different excimer lasers (P>0.05). There was a statistically significant difference in mean UDVA and J0 at 6-month and 12-month after PRK among the three groups, with no statistically significant difference between Alcon Wavelight and Schwind Amaris lasers, while both of the prior lasers showed a significant difference with the Technolas laser. The highest and lowest changes in the magnitude of J0 in 6-month and 12-month follow-ups were seen for the Alcon Wavelight and Technolas groups, respectively. Both Schwind Amaris and Technolas had a small hyperopic SE while the Alcon Wavelight's SE was minimally myopic. This difference in SE between Alcon Wavelight and both Schwind Amaris and Technolas reached statistical significance. While all three lasers performed well in reducing preoperative astigmatism; however, the Alcon Wavelight and Schwind Amaris were more effective in correcting astigmatism than the Technolas. The difference between the Alcon Wavelight and Schwind Amaris did not reach statistical significance.

A Standardized Protocol of Simultaneous Transepithelial Phototherapeutic Keratectomy (PTK) Followed by Corneal Collagen Crosslinking for Keratoconus.

To report outcomes in patients with progressive keratoconus who underwent a standardized protocol of transepithelial phototherapeutic keratectomy (t-PTK) laser followed by accelerated corneal collagen crosslinking (CXL). All patients with progressive keratoconus undergoing our protocol at a London clinic between 2019 and 2023 were included. The protocol involved t-PTK at 58-μm central ablation depth at a 9-mm treatment zone on the Schwind Amaris 1050RS platform. Preoperative K readings of 43.0D (both K1 and K2) were inputted for all cases. Patients then underwent CXL with a pulsed-light accelerated protocol (30 mW/cm2 for 8 minutes of UVA exposure time with 1 second on/1 second off). Seventy-nine eyes from 55 patients were included with an average follow-up of 12 months (range 6-24 months). Both mean uncorrected distance visual acuity (UDVA) and best spectacle-corrected visual acuity improved significantly from 0.42 preoperatively to 0.29 postoperatively (P < 0.01) and 0.11 to 0.06 postoperatively (P < 0.01), respectively. The refractive cylinder reduced significantly from -3.07D to -2.63D (P < 0.05). The mean Km improved from 46.15D to 45.44D (P < 0.01) and mean Kmax from 54.03D to 52.52D (P < 0.01). 77% of eyes (n = 61) exhibited Kmax improvement postoperatively, and 56% showed an improvement in UDVA (n = 44). 16% (n = 13) had worsening of vision, but of these, only 1 patient had visual loss of more than 2 lines. No eyes had corneal haze reported at the final follow-up, and none required additional treatment. This standardized simultaneous t-PTK and CXL protocol is safe and effective for the treatment of progressive keratoconus, providing visual, refractive, and topographic improvements.

Static and Dynamic Cyclotorsion Compensation with the Schwind Amaris Laser System: Twelve-Month Refractive and Visual Outcomes

Static and Dynamic Cyclotorsion Compensation with the Schwind Amaris Laser System: Twelve-Month Refractive and Visual Outcomes

Tetracaine Effect on Pain Control within the First Day after Trans-Epithelial Photorefractive Keratectomy

Background: This study was carried out to evaluate the effect of non-preserved tetracaine 0.5% on pain alleviation in the first 24 hr after Trans-epithelial Photorefractive Keratectomy (TPRK) excimer laser surgery.&#x0D; Methods: This quasi-experimental study was conducted on 50 patients who were candidates for TPRK surgery using SCHWIND AMARIS 1050RS (eye-tech-solutions, Germany) excimer laser. One eye randomly received standard treatment including the eye drops of betamethasone, chloramphenicol, artificial tear, diclofenac, and diclofenac tablet (25 mg daily), and the fellow eye received standard treatment plus non-preserved tetracaine 0.5% drop every 4 hr. Post-operative pain was the main outcome measure, and the secondary outcome measures including burning sensation, epiphora, foreign body sensation, and photophobia were compared using Fisher’s exact test and ANOVA with a significance level of 0.05.&#x0D; Results: Nineteen patients (38%) were male and 31 (62%) were female. Thirty patients (60%) reported no pain. The numeric scale of pain showed that the severity of pain was 4.4±0.8 for the cases’ eyes and 4.5±0.6 for the controls’ eyes, but the difference was not significant (p=0.75). Also, there was no difference regarding the burning sensation (p=0.49), epiphora (p=0.16), foreign body sensation (p=0.44), and photophobia (p=0.19). No significant difference was noted between the two groups.&#x0D; Conclusion: Administering the eye drop of non-preserved tetracaine 0.5% every 4 hr had no significant effect on pain alleviation within the first day after TPRK surgery.

Comparison of Conventional Versus Trans-Epithelial Photorefractive Keratectomy in Hyperopia Treatment: A Contralateral Study

Background: This study was planned to compare Trans - epithelial Photorefractive Keratectomy (TPRK) and Alcohol Assisted Photorefractive Keratectomy (AAPRK) laser vision correction in hyperopia and compound hyperopic astigmatism.&#x0D; Methods: This quasi-experimental study was conducted on patients with hyperopia and hyperopic-astigmatism, whose eye laterality was randomly assigned to undergo TPRK versus AAPRK using SCHWIND AMARIS 1050RS (SCHWIND eye-tech-solutions, Germany). Follow up time was 1, 3, 6 and 12 months after surgery.&#x0D; Results: 112 eyes of 56 patients with mean age of 32.6 years included, of which 51.8% were female and 48.2% were male. Both TPRK and AAPRK methods were able to correct hyperopia and astigmatism safely and efficiently (p&lt;0.05 in all cases). Postoperative vision characteristics were similar in both methods (p=0.23 for sphere, p=0.52 for cylinder, p=0.064 for axis, and p=0.35 for BCVA) postoperatively. Corneal haze was observed in 44% of the patients with a direct strong correlation with hyperopia severity (r=0.607). Post-operative pain was observed in 60% of the patients with a direct weak correlation with hyperopia severity (r=0.27). Mild photophobia was seen in 42% of the patients with a direct weak correlation between photophobia and hyperopia severity (r=0.36). Epithelial healing time lasted an average of 3.48 days and there was a direct and moderate correlation with hyperopia severity (r=0.4). Safety index in TPRK and AAPRK was 0.54 and 0.45, respectively, with no significant difference (p=0.42); Efficacy index was 0.96 and 0.9 in TPRK and AAPRK, respectively and there was no significant difference between two groups (p=0.23). No complication was observed in all of the patients.&#x0D; Conclusion: TPRK and AAPRK laser vision correction are both safe and efficient in hyperopia and compound hyperopic astigmatism. There is no significant difference regarding epithelial healing time, post-operative pain and haze formation between two procedures.

Cross Sectional Analysis of Impact of Seasonal Changes on Excimer Laser Ablation Performance on Polymethyl Methacrylate (PMMA).

Seasonal changes and varying degree of corneal hydration has been linked to excimer laser corneal ablation rates. The use of PMMA as a calibration material in refractive lasers is well established. However, PMMA ablation may be equally affected by seasonal variations in temperature and humidity, in turn affecting the calibration process. The aim of this work is to analyze the effect of seasonal changes in PMMA performance using SCHWIND AMARIS laser system. PET and PMMA ablations conducted in climate-controlled environment with 826 consecutive AMARIS systems manufactured over 6 years were retrospectively analyzed. Lasers were stratified depending on seasons and months of the year. Metrics like single laser pulse fluence, nominal number of laser pulses, mean performance, standard deviation, and technical performance of system were compared to global average values. Cyclic winter-summer variation was confirmed with seasons winter and summer showing statistically significant variations with respect to global values. Metric technical performance showed deeper PMMA ablation performance in summertime, with maximum seasonal deviation of 6%. Results were consistently confirmed in seasonal as well as monthly analyses. These findings could help minimize variance among laser systems by implementing compensation factors depending on seasons such that laser systems installed worldwide follow the same trend line of variation.

Early Outcomes of Two Treatment Modes of PresbyLASIK: Monocular vs. Micro-Monovision

To report the visual, refractive and subjective outcomes of presbyLASIK for the correction of presbyopia. Monocular (20 eyes) or micro-monovision (12 eyes) presbyLASIK was performed on a total of 32 eyes in 16 patients (50% female, average age 55±4.6 years) using the Zeiss VisuMax 400Hz femtosecond and Schwind Amaris 1050RS excimer laser platform. Predictability, safety and efficacy were assessed and compared at 4-6 weeks, 3 months and 6 months. Results were considered significant if P < 0.05. For monocular treatments, average postoperative spherical equivalent (SE) was 0.1±0.1 D and -0.86±0.5 D at 4-6 weeks postoperatively for distance and near eyes respectively; 90% eyes achieved SE ±1.0 D of the target. Postoperative binocular uncorrected distance (UDVA), intermediate (UIVA) and near visual acuity (UNVA) were -0.03±0.1 LogMAR (20/20), 0.09±0.26 LogMAR (N4) and 0.29±0.11 LogMAR (N6) respectively with 90% patients achieving binocular UDVA of 20/20 or better. For micro-monovision treatments, average postoperative SE was -0.33±0.51 D and -1.60±0.78 D at 4-6 weeks postoperatively for distance and near eyes respectively; 100% eyes achieved SE ±1.0 D of the target. Postoperative binocular UDVA, UIVA and UNVA were 0.05±0.16 LogMAR (20/20), -0.02±0.10 LogMAR (N3) and 0.23±0.08 LogMAR (N5) respectively with 67% patients achieving binocular UDVA of 20/20 or better. Monocular and micro-monovision presbyLASIK are both effective options for the treatment of presbyopia. Monocular treatments are more likely to be well tolerated by patients who prefer to preserve exceptional distance vision, while micro-monovision treatments may be better suited to patients who can tolerate compromises in distance vision in order to attain greater intermediate vision function.

Long-Term Outcomes of Excimer Laser-Assisted Penetrating Keratoplasty Using a Commercially Available Laser System - A Retrospective Case Series.

Favorable functional outcomes have been reported after excimer laser-assisted penetrating keratoplasty (EXL PKP). But this technique has not been widely adopted, and there are reports on EXL PKP from only a very limited number of institutions. Some of these results refer to operations carried out with laser systems that are not commercially available. In this retrospective case series, we report the long-term outcome of EXL PKP using the Schwind Amaris 500E laser system. This retrospective consecutive case series included 30 eyes of 29 patients who had undergone EXL PKP between 2010 and 2013. Primary outcome measures were topographic astigmatism and visual acuity. Secondary outcome measures were the rates of graft rejection and graft failure, and the rate of grafts with an endothelial cell density below 500 cells/mm2. Survival analyses were carried out for the following endpoints: visual acuity, rate of graft rejection, and rate of grafts with endothelial cell densities higher than 500 cells/mm2. The median interquartile range (IQR) duration of follow-up was 45 (36) months. The indications for PKP were keratoconus (n = 21), corneal scarring (n = 6), Fuchs endothelial dystrophy (n = 1), and corneal dystrophy other than Fuchs endothelial dystrophy (n = 2). The median (IQR) topographic astigmatism at the end of the follow-up period was 5.3 (2.9) D. Forty-five months after surgery, 73% of all eyes had a visual acuity better than 0.3 LogMAR. The rate of graft rejection after 45 months of follow-up was 32%. All eyes maintained endothelial cell densities higher than 500 cells/mm2. There was no graft failure. EXL PKP is a safe and effective surgical procedure. No general conclusions can be drawn on the refractive outcome of EXL PKP. Potential advantages, such as a higher degree of graft-host congruity, that could possibly improve the refractive outcome should be weighed against the higher costs of EXL PKP.

Comparison of transepithelial and conventional photorefractive keratectomy in myopic and myopic astigmatism patients: a randomized contralateral trial

BackgroundTo assess transepithelial photorefractive keratectomy (tPRK) in terms of corneal epithelial healing rate, postoperative pain, postoperative discomfort, and visual and refraction outcomes compared to mechanical epithelial debridement PRK (mPRK) and alcohol-assisted PRK (aaPRK).MethodsIn this double-masked, randomized clinical trial, thirty-nine patients underwent tPRK in one eye and mPRK in the fellow eye (arm A), and 33 patients underwent tPRK in one eye and aaPRK in the contralateral eye (arm B). All surgical procedures were done using the Schwind Amaris excimer laser. The area of corneal epithelial defect in all eyes was captured and analyzed using ImageJ software.ResultsMean epithelial healing time was respectively 3.74 ± 0.82 and 3.59 ± 0.79 days in tPRK versus mPRK (P = 0.21) in arm A, and 3.67 ± 0.92 and 3.67 ± 0.74 days in tPRK versus aaPRK (P = 1.00) in arm B. Accounting for the initial corneal epithelial defect area, the epithelial healing rate was faster in conventional PRK groups compared to tPRK (both P<0.001) in both arms. However, there was no significant difference in safety, efficacy, spherical equivalent refractive accuracy, or corneal haze development between tPRK and conventional PRK groups (all P > 0.05).ConclusionsAll three methods are effective in terms of visual and refractive outcomes. However, although time to complete re-epithelialization was similar with the three methods, the epithelial healing rate was faster in conventional PRK considering the initial corneal epithelial defect area, and the patients experienced less pain and discomfort in the first postoperative day.Trial registrationIRCT, IRCT20200317046804N1. Retrospectively registered 5 May 2020.

Comparison of clinical outcomes between Wavelight Allegretto Eye-Q and Schwind Amaris 1050RS in high myopic astigmatism

Purposes: To compare clinical outcomes between Wavelight Allegretto Eye-Q 400Hz and Schwind Amaris 1050RS in high myopic astigmatism. Methods: non-randomized, controlled, interventional study of 90 eyes with at least 1.5diopter astigmatism, assigned into two groups depends to the L machine and followed up three months post-op. Primary outcomes include uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), subjective refraction spherical equivalent (SRSE), cylinder, safety and efficacy indices, refractive predictability and stability; and optical aberration and contrast sensitivity changes after surgery. Besides, Alpins method about residual astigmatism is also analyzed and compared between groups. Results: Safety index of Schwind Amaris and Allegretto group is 1.011 ± 0.169 and 1.007 ± 0.055 (p = 0.510); effective index is 1 ± 0.032 and 0.991 ± 0.077 (p = 0.567; stability index is 0.003 and 0.1 (p = 0.134); predictability index within [±0.5D] after three-month postop is 91.1% and 95.6% (p = 0.398), respectively. Post-op residual astigmatism in Schwind Amaris and Allegretto group is -0.139 ± 0.22 and -0.183 ± 0.27 (p = 0.396). Regarding Alpins method in astigmatic analysis of Schwind Amaris and Allegretto groups: SIA (surgically induced astigmatism) is 1.792 ± 0.534 and 1.920 ± 0.588 (p = 0.284); AE (angle of error) is 1.04 ± 2.881 and -0.08 ± 3.790 (p = 0.119); CI (correction index) is 0.98 ± 0.107 and 1.02 ± 0.142 (p = 0.165); SAS (Success of Astigmatism Surgery) is 92.01 ± 12.77 and 89.78 ± 16.32 (p = 0.472), respectively. Contrast sensitivity and higher optical aberration changes after surgery between two groups are insignificant differences (p &gt; 0.05). Conclusions: Clinical outcomes of both lasers machine are good. There is no significant differences in residual astigmatism and high-order aberrations or contrast sensitivity changes after surgery between two groups.

Efficacy and safety of single-step transepithelial photorefractive keratectomy with the all-surface laser ablation SCHWIND platform without mitomycin-C for high myopia: A retrospective study of 69 eyes.

Studies suggest that transepithelial photorefractive keratectomy (TransPRK) with the all-surface laser ablation (ASLA)-SCHWIND platform is effective and safe for both low-moderate myopia and high myopia. In most studies, mitomycin-C is administered immediately after surgery to prevent corneal opacification (haze), which is a significant complication of photorefractive keratectomy in general. However, there is evidence that adjuvant mitomycin-C induces endothelial cytotoxicity. Moreover, a recent study showed that omitting adjuvant mitomycin-C did not increase haze in low-moderate myopia. The present case-series study examined the efficacy, safety, and haze rates of eyes with high myopia that underwent ASLA-SCHWIND TransPRK without adjuvant mitomycin-C. All consecutive eyes with high myopia (≤-6 D) that were treated in 2018-2020 with the SCHWIND Amaris 500E® TransPRK excimer laser without adjuvant mitomycin-C in a tertiary-care hospital (France) and were followed up for 6 months were identified. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and spherical equivalent (SE) were recorded before and after surgery. Postoperative haze was graded using the 4-grade Fantes scale. Efficacy rate (frequency of eyes with 6-month UCVA ≤0.1 logMAR), safety rate (frequency of eyes that lost <2 BSCVA lines), predictability (frequency of eyes with 6-month SE equal to target SE±0.5 D), efficacy index (mean UCVA at 6 months/preoperative BSCVA), and safety index (BSCVA at 6 months/preoperative BSCVA) were computed. Sixty-nine eyes (38 patients) were included. Mean preoperative and 6-month SE were -7.44 and -0.05 D, respectively. Mean 6-month UCVA and BSCVA were 0.00 and -0.02 logMAR, respectively. Efficacy rate and index were 95.7% and 1.08, respectively. Safety rate and index were 95.7% and 1.13, respectively. Predictability was 85.5%. Grade 3-4 haze never arose. At 6 months, the haze rate was zero. ASLA-SCHWIND TransPRK without mitomycin-C appears to be safe as well as effective and accurate for high myopia.

Особенности интраоперационной пахиметрии при рефракционном лазерном кератомилёзе миопии методом FemtoLASIK

Comparison of preoperative pachymetry with intraoperative pachymetry; evaluation of the features of intraoperative pachymetry during surgery, practical application. Material and methods. The analysis of the results of 58 operations for myopia by the FemtoLASIK method was carried out. Femtosecond laser is a Ziemer femtosecond laser. Refractive ablation – with a SCHWIND Amaris 750 S excimer laser with integrated OCP. Pachymetry was performed in the center of the cornea at the diagnostic stage and during the operation: before the formation of the flap, after the formation and removal of the flap, and after the completion of ablation. Results. It was statistically reliably revealed that intraoperative pachymetry during FemtoLASIK differs from the planned one. The regularity is associated with the process of hydration of the corneal stroma during vacuum fixation of a femtosecond laser and with the process of dehydration during laser ablation. Conclusion. The obtained results allow us to speak about step-by-step control of the corneal thickness during FemtoLASIK and comparison of the planned parameters with those measured during the operation, as a way to timely detect deviations from the operation plan and, as a result, reduce the risk of pathological corneal thinning. In cases where the values of the corneal thickness in the central zone before the operation and the flap thickness correspond to the preoperative plan, the discrepancy between the planned RST indicator and its actual measured value during the operation is not critical. Key words: FemtoLASIK, intraoperative pachymetry, residual thickness of the stromal bed, hydration, corneal dehydration.

Effect of laser beam truncation (pinhole), (ordered) dithering, and jitter on residual smoothness after poly(methyl methacrylate) ablations, using a close-to-Gaussian beam profile

Abstract Smoother surfaces after laser vision correction have been widely accepted as a factor for improving visual recovery regardless of the used technique (PRK, LASIK, or even SMILE). We tested the impact of laser beam truncation, dithering (expressing a continuous profile on a basis of lower resolution causing pixels to round up/down the number of pulses to be placed), and jitter (a controlled random noise (up to ±20 µm in either direction) added to the theoretical scanner positions) on residual smoothness after Poly(methyl methacrylate) (PMMA) ablations, using a close-to-Gaussian beam profile. A modified SCHWIND AMARIS system has been used providing a beam profile with the following characteristics: close-to-Gaussian beam profile with full width at half maximum (FWHM) of 540 µm, 1050 Hz. Laser parameters have been optimized following Invest. Ophthalmol. Vis. Sci., vol. 58, no. 4, pp. 2021–2037, 2017, the pulse energy has been optimized following Biomed. Opt. Express vol. 4, pp. 1422–1433, 2013. For the PMMA ablations, two configurations (with a 0.7 mm pinhole and 0.75 mJ and without pinhole and 0.9 mJ (for fluences of 329 mJ/cm2 and 317 mJ/cm2 and corneal spot volumes of 174 and 188 pl)) were considered, along with two types of lattices (with and without ordered dithering to select the optimum pulse positions), and two types of spot placement (with and without jitter). Real ablations on PMMA (ranging from −12D to +6D with and without astigmatism of up to 3D) completed the study setup. The effect of the 2 × 2 × 2 different configurations was analyzed based on the roughness in ablation estimated from the root mean square error in ablation. Truncation of the beam is negatively associated to a higher level of residual roughness; ordered dithering to select the optimum pulse positions is positively associated to a lower level of residual roughness; jitter is negatively associated to a higher level of residual roughness. The effect of dithering was the largest, followed by truncation, and jitter had the lowest impact on results. So that: Dithering approaches help to further minimize residual roughness after ablation; minimum (or no) truncation of the beam is essential to minimize residual roughness after ablation; and jitter shall be avoided to minimize residual roughness after ablation. The proposed model can be used for optimization of laser systems used for ablation processes at relatively low cost and would directly improve the quality of results. Minimum (or no) truncation of the beam is essential to minimize residual roughness after ablation. Ordered dithering without jitter helps to further minimize residual roughness after ablation. Other more complex dithering approaches may further contribute to minimize residual roughness after ablation.

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

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

SmartSurfACE transepithelial photorefractive keratectomy with mitomycin C enhancement after small incision lenticule extraction

BackgroundTo evaluate predictability, stability, efficacy, and safety of transepithelial photorefractive keratectomy (TPRK) using smart pulse technology (SPT) (SmartSurface procedure) of Schwind Amaris with mitomycin C for correction of post small incision lenticule extraction (SMILE) myopic residual refractive errors.MethodThis study is a prospective, non-comparative case series conducted at a private eye centre in Ismailia, Egypt, on eyes with post-SMILE myopic residual refractive errors because of undercorrection or suction loss (suction loss occurred after the posterior lenticular cut and the creation of side-cuts; redocking was attempted, and the treatment was completed in the same session with the same parameters) with myopia or myopic astigmatism. The patients were followed up post-SMILE for six months before the SmartSurface procedure, and then they were followed up for one year after that. TPRK were performed using Amaris excimer laser at 500 kHz. The main outcomes included refractive predictability, stability, efficacy, safety and any reported complications.ResultsThis study included 68 eyes of 40 patients out of 1920 total eyes (3.5%) with post-SMILE technique myopic residual refractive errors. The average duration between the SMILE surgery and TPRK was 6.7 ± 0.4 months (range 6 to 8 months). The mean refractive spherical equivalent (SE) was within ± 0.50 D of plano correction in 100% of the eyes at 12 months post-TPRK. Astigmatism of < 0.50 D was achieved in 100% of the eyes. The mean of the residual SE error showed statistically significant improvement from preoperative − 1.42 ± 0.52 D to 0.23 ± 0.10 D (P < 0.0001). Uncorrected distance visual acuity (UDVA) (measured by Snellen's chart and averaged in logMAR units) was improved significantly to 0.1 ± 0.07 (P < 0.0001). UDVA was 0.2 logMAR or better in 100% of the eyes, 0.1 logMAR or better in 91.2% of the eyes, and 0.0 logMAR in 20.6% of the eyes. Corrected distance visual acuity (CDVA) remained unchanged in 79.4% of eyes. 14.7% of eyes gained one line of CDVA (Snellen). 5.9% of eyes gained two lines of CDVA (Snellen).ConclusionTransepithelial photorefractive keratectomy using smart pulse technology with mitomycin C enhancement after SMILE is a safe, predictable, stable, and effective technique.

Thermographic Behavior of the Cornea During Treatment With Two Excimer Laser Platforms.

PurposeTo investigate the temperature of the cornea during treatment with the excimer laser using two platforms, Nidek EC-5000 and Schwind Amaris 750S.MethodsA prospective case series study was conducted in a reference center in Mexico City including patients aged 18 years or older who had any type of ametropia and underwent excimer laser refractive surgery. The patients had measurements of corneal temperature with an infrared camera before, during, and after ablation treatment. Results of prior corneal surface temperature, temperatures during excimer laser surgery, and delta temperature for each platform were analyzed and compared.ResultsA total of 107 eyes were analyzed. Mean baseline temperature was 32.7 ± 1.03°C for the Nidek group and 31.5 ± 1.4°C for the Amaris group. Mean maximum temperature was 39.94 ± 1.3°C for the Nidek group and 35.6 ± 1.5 °C for the Amaris group. Delta temperature was higher in the Nidek group than in the Amaris group. There were statistically significant associations between treated micrometers, treated diopters, and time in the Nidek group and no such associations in the Amaris group.ConclusionsThe different excimer laser devices used and the variety in the optical design, together with different software ablation algorithms, resulted in different levels of thermal loading; peak temperature rose in all measurements. Eyes treated with Nidek reached temperatures that doubled those found with Amaris.Translational RelevanceThe correlation between Delta of temperature with defocus, depth, and treatment time is different regarding excimer laser generation.

One-Year Visual and Refractive Outcomes following LASIK for Myopia and Myopic Astigmatism with MEL 90 versus Schwind Amaris 750S Excimer Laser: A Comparative Study.

Purpose To compare clinical outcomes following LASIK for myopia performed with MEL 90 vs. Schwind Amaris 750S excimer laser. Methods Data were collected retrospectively for patients who underwent Femto-LASIK, using the MEL 90 and Schwind Amaris 750S excimer laser for correction of myopia and myopic astigmatism within the range of −1.00 to −10.00 D SE from January 2013 till June 2018. Outcomes were analysed at 12 months for safety, efficacy, enhancement rate, and long-term complications. Results A total of 328 eyes of 328 patients were analysed. One hundred and sixty-three eyes were treated with Schwind Amaris and the remaining 165 eyes with the MEL 90 laser. Twelve months postoperatively, the mean UDVA, CDVA, residual SE, and cylinder in the Amaris group were −0.10 ± 0.09 logMAR, −0.14 ± 0.06 logMAR, −0.21 ± 0.22 D, −0.13 ± 0.18 D versus −0.05 ± 0.07 logMAR, −0.09 ± 0.08 logMAR, −0.23 ± 0.23 D, and −0.14 ± 0.21 D for the MEL 90 group (p values >0.05). For the Amaris group, safety and efficacy indices were 1.12 and 1.02, whereas for the MEL 90 group, these indices were 1.08 and 1.00, respectively. No eye in either group had any postop flap-related complications, infectious keratitis, diffuse lamellar keratitis, or keratectasia. Two eyes in the Amaris and 4 eyes in MEL 90 group required enhancement for the progression of myopia. Conclusion At 12 months, both Schwind Amaris 750S and MEL 90 lasers demonstrated comparable clinical outcomes for myopic LASIK in a single surgeon setting.