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"LASIK"
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Comparison of outcomes after topography-modified refraction versus wavefront-optimized versus manifest topography-guided LASIK
2020
Background
To compare the outcomes of myopia and myopic astigmatism corrected with topography-modified refraction laser in situ keratomileusis (TMR-LASIK), wavefront-optimized (WFO) LASIK, and topography-guided (TG) LASIK with a correction target based on the manifest refraction (manifest TG-LASIK).
Methods
This observational, retrospective cohort study included patients who underwent LASIK using the WaveLight® EX500 excimer laser to correct myopia and myopic astigmatism between August 2016 and July 2017. Patients who underwent TMR-LASIK (85 patients), WFO-LASIK (70 patients), or manifest TG-LASIK (40 patients) were enrolled, and only one eye from each patient was analyzed. All participants underwent measurement of the uncorrected distance visual acuity (UDVA), best-corrected distance visual acuity (BCVA), manifest refraction, vector analysis of astigmatic change, corneal topography, and corneal wavefront analysis at baseline and at every posttreatment visit.
Results
Three months postoperatively, a UDVA of 0.0 logMAR or better and manifest refraction spherical equivalent (MRSE) within ±0.5 diopters (D) did not differ across the TMR-, WFO-, and manifest TG-LASIK groups. However, the residual cylinder in the TMR group was significantly larger than that in the WFO and manifest TG groups. The magnitude of error in the TMR group measured using astigmatism vector analysis was significantly higher than that in the WFO and manifest TG groups.
Conclusions
Although these three LASIK platforms achieved the predicted surgical outcomes, TMR-LASIK overcorrected astigmatism and showed a higher residual postoperative astigmatism compared with WFO- and manifest TG-LASIK.
Journal Article
Novel Technique to Improve the Efficacy of Corneal Cross Linking in Cases of Post LASIK Ectasia
by
Elkitkat, Rania Serag
,
Omar Yousif, Mohamed
,
Abdelsadek Alaarag, Noha
in
Comparative analysis
,
corneal cross-linking
,
Crosslinked polymers
2023
The aim of the present study was to validate the use of a novel technique that can improve the efficacy of corneal cross-linking (CXL) in cases with post LASIK ectasia.
This is a retrospective, comparative study that was conducted on patients who sought medical advice at Ain Shams University Hospitals and Maadi Eye Subspeciality Center, Cairo, Egypt. It included two groups of patients with post LASIK ectasia. Group 1 included patients who performed our proposed protocol (topo-guided PRK, followed by customized phototherapeutic keratectomy \"PTK\" to transmit the laser treatment to the corneal stroma, then CXL). For group 2, accelerated CXL was performed. Subjective refraction and relevant topographic/tomographic parameters (Sirius topographer) compared between the two groups. Recorded follow-ups included the 2 to 3-month follow-up visit and the last visit (mean ± SD of 17.2 months ± 10.2).
Patients of group 1 (22 eyes of 22 patients) experienced significant improvements in most of the evaluated parameters at the 2- to 3-month follow-up visit and showed stability of the ectatic condition at the last follow-up visit, whereas patients of group 2 (10 eyes of 10 patients) showed stability of their ectatic condition at the 2- to 3-month follow-up visit, and one patient developed ectasia progression at the last follow-up visit.
The present study validates the use of our novel protocol in cases having post LASIK ectasia with proven efficacy, safety, and stability, providing regularization for the corneal surface while simultaneously avoiding the unnecessary loss of cross-linking effect within the LASIK flap that no longer shares in the corneal biomechanical strength.
Journal Article
Non adherence of flap following microkeratome-assisted laser-assisted in situ keratomileusis: A case report and review of literature
2020
A 28-year-old male underwent microkeratome assisted Laser-assisted in situ keratomileusis (LASIK) for, myopia. On postoperative day 1, patient had a large epithelial defect in OD. The corneal epithelial defect healed within 72 hours, but sub-optimal vision persisted. The patient was referred for further management to us. On evaluation, patient had non-healing of flap margin at 5 o'clock. Fluoroscein stain revealed no corneal epithelial defect, but a large pool of dye beneath the LASIK flap. A clinical diagnosis of non-adherence of LASIK flap was considered. Application of bandage contact lens was done. LASIK flap completely healed in 1 week. Possible etiologies are discussed and literature is reviewed.
Journal Article
Comparison of prophylactic higher fluence corneal cross-linking to control, in myopic LASIK, one year results
by
Asimellis, George
,
Karabatsas, Costas
,
Kanellopoulos, John
in
accelerated high-fluence collagen cross-linking
,
Biomechanics
,
Care and treatment
2014
To compare 1-year results: safety, efficacy, refractive and keratometric stability, of femtosecond myopic laser-assisted in situ keratomileusis (LASIK) with and without concurrent prophylactic high-fluence cross-linking (CXL) (LASIK-CXL).
We studied a total of 155 consecutive eyes planned for LASIK myopic correction. Group A represented 73 eyes that were treated additionally with concurrent prophylactic high-fluence CXL; group B included 82 eyes subjected to the stand-alone LASIK procedure. The following parameters were evaluated preoperatively and up to 1-year postoperatively: manifest refractive spherical equivalent (MRSE), refractive astigmatism, visual acuity, corneal keratometry, and endothelial cell counts. We plotted keratometry measurements pre-operatively and its change in the early, interim and later post-operative time for the two groups, as a means of keratometric stability comparison.
Group A (LASIK-CXL) had an average postoperative MRSE of -0.23, -0.19, and -0.19 D for the 3-, 6-, and 12-month period, respectively, compared to -6.58±1.98 D preoperatively. Flat keratometry was 37.69, 37.66, and 37.67 D, compared to 43.94 D preoperatively, and steep keratometry was 38.35, 38.36, and 38.37 D, compared to 45.17 D preoperatively. The predictability of Manifest Refraction Spherical Equivalent (MRSE) correction showed a correlation coefficient of 0.979. Group B (stand-alone LASIK) had an average postoperative MRSE of -0.23, -0.20, and -0.27 D for the 3-, 6-, and 12-month period, respectively, compared with -5.14±2.34 D preoperatively. Flat keratometry was 37.65, 37.89, and 38.02 D, compared with 43.15 D preoperatively, and steep keratometry was 38.32, 38.57, and 38.66 D, compared with 44.07 D preoperatively. The predictability of MRSE correction showed a correlation coefficient of 0.970. The keratometric stability plots were stable for the LASIK CXL group and slightly regressing in the standard LASIK group, a novel stability evaluation metric that may escape routine acuity and refraction measurements.
Application of prophylactic CXL concurrently with myopic LASIK surgery appears to contribute to improved refractive and keratometric stability compared to standard LASIK. The procedure appears safe and provides a new potential for LASIK correction.
Journal Article
Complications of laser-assisted in situ keratomileusis
by
Sahay, Pranita
,
Bafna, Rahul Kumar
,
Sharma, Namrata
in
Care and treatment
,
Cataract
,
Complications
2021
Laser-assisted in situ keratomileusis (LASIK) is one of the most commonly performed kerato-refractive surgery globally. Since its introduction in 1990, there has been a constant evolution in its technology to improve the visual outcome. The safety, efficacy, and predictability of LASIK are well known, but complications with this procedure, although rare, are not unknown. Literature review suggests that intraoperative complications include suction loss, free cap, flap tear, buttonhole flap, decentered ablation, central island, interface debris, femtosecond laser-related complications, and others. The postoperative complications include flap striae, flap dislocation, residual refractive error, diffuse lamellar keratitis, microbial keratitis, epithelial ingrowth, refractive regression, corneal ectasia, and others. This review aims to provide a comprehensive knowledge of risk factors, clinical features, and management protocol of all the reported complications of LASIK. This knowledge will help in prevention as well as early identification and timely intervention with the appropriate strategy for achieving optimal visual outcome even in the face of complications.
Journal Article
Topography-modified refraction (TMR): adjustment of treated cylinder amount and axis to the topography versus standard clinical refraction in myopic topography-guided LASIK
2016
To evaluate the safety, efficacy, and contralateral eye comparison of topography-guided myopic LASIK with two different refraction treatment strategies.
Private clinical ophthalmology practice.
A total of 100 eyes (50 patients) in consecutive cases of myopic topography-guided LASIK procedures with the same refractive platform (FS200 femtosecond and EX500 excimer lasers) were randomized for treatment as follows: one eye with the standard clinical refraction (group A) and the contralateral eye with the topographic astigmatic power and axis (topography-modified treatment refraction; group B). All cases were evaluated pre- and post-operatively for the following parameters: refractive error, best corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), topography (Placido-disk based) and tomography (Scheimpflug-image based), wavefront analysis, pupillometry, and contrast sensitivity. Follow-up visits were conducted for at least 12 months.
Mean refractive error was -5.5 D of myopia and -1.75 D of astigmatism. In group A versus group B, respectively, the average UDVA improved from 20/200 to 20/20 versus 20/16; post-operative CDVA was 20/20 and 20/13.5; 1 line of vision gained was 27.8% and 55.6%; and 2 lines of vision gained was 5.6% and 11.1%. In group A, 27.8% of eyes had over -0.50 diopters of residual refractive astigmatism, in comparison to 11.7% in group B (
<0.01). The residual percentages in both groups were measured with refractive astigmatism of more than -0.5 diopters.
Topography-modified refraction (TMR): topographic adjustment of the amount and axis of astigmatism treated, when different from the clinical refraction, may offer superior outcomes in topography-guided myopic LASIK. These findings may change the current clinical paradigm of the optimal subjective refraction utilized in laser vision correction.
Journal Article
Comparison of clinical outcomes of a corneal wavefront- and topography-guided platforms for laser in situ keratomileusis on virgin eyes: an expanded cohort study
2024
Purpose
To compare the clinical outcomes of myopiacorrected with corneal-wavefront-guided (CWG) laser in situ keratomileusis (LASIK) with AMARIS 1050S (SCHWIND eye-tech-solutions GmbH & Co. KG) and corneal-topography-guided (CTG) LASIK with WaveLight EX500 (Alcon Laboratories, Fort Worth, TX).
Methods
In this prospective, pseudo-randomized expanded cohort study, a total of 266 patients were subjected to binocular LASIK surgery, either with WaveLight EX500 (WaveLight group) or Amaris 1050S (AMARIS group) platforms. Data related to right eyes were selected for analysis. Corneal higher-order aberration (HOA) was selected as the primary endpoint; while visual acuity and refraction were the secondary endpoints. All the endpoints were assessed at 3 months postoperatively.
Results
There were 134 eyes in the AMARIS group and 132 eyes in the WaveLight group. After 3 months of postoperative follow-up, spherical and coma aberrations were significantly lower (
P
< 0.05) in the WaveLight group (spherical aberration: − 0.104 ± 0.199 µm; coma aberration: − 0.117 ± 0.202 µm) in comparison with the AMARIS group (spherical aberrations: 0.254 ± 0.146 µm; coma aberrations: 0.316 ± 0.297 µm). In the AMARIS group, 96.3% of the eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 while in the WaveLight group, 96.2% of the eyes achieved an UDVA of 20/20. Furthermore, the mean postoperative manifest refraction spherical equivalent (MRSE) was − 0.02 ± 0.28 in the AMARIS group and − 0.05 ± 0.21 in the WaveLight group (
P
= 0.34).
Conclusions
Both WaveLight EX500 and Amaris 1050S LASIK showed excellent refractive and visual outcomes. In addition, the WaveLight group showed minimal spherical and coma aberrations when compared to the AMARIS group.
Journal Article
Recent Advances in Refractive Surgery: An Overview
2024
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.
Journal Article
Comparative analysis of outcomes following topography-guided laser in situ keratomileusis using manifest refraction versus a new topographic analysis algorithm
by
Dandapani, Ramamurthy
,
Soundarya, B
,
Sachdev, Gitansha S
in
Acuity
,
Algorithms
,
Astigmatism - surgery
2023
Purpose:
To compare the visual outcomes following topography-guided laser in situ keratomileusis (LASIK) treatment using manifest refraction versus a new topography analysis software.
Methods:
A prospective, randomized, observer-masked contralateral study was conducted in the refractive services of a tertiary eye care hospital in South India. Analysis of visual outcomes, corneal higher-order aberrations, and contrast sensitivity were performed at 3 months postoperative visit following uneventful topography-guided LASIK using the Wavelight EX500. One eye was treated with the Contoura platform using manifest refraction (Contoura), while the contralateral eye was treated using an ablation profile planned by the Phorcides Analytic Engine (Phorcides).
Results:
Sixty eyes of 30 patients were included in the study. At 3 months postoperative visit, the uncorrected distance visual acuity (UDVA) in the Contoura and Phorcides groups was logarithm of the minimal angle of resolution (logMAR) 0.04 ± 0.07 and logMAR 0.06 ± 0.1, respectively (P = 0.483). Postoperative manifest refractive spherical error (MRSE) was 0.12 ± 0.22 and − 0.06 ± 0.20 D in the Contoura and Phorcides groups, respectively (P = 0.338). Although higher number of eyes demonstrated a gain in one or more lines of corrected distance visual acuity (CDVA) in the Contoura group (16.6% vs. 6.6%), the difference was not statistically significant (P = 0.361). Vector analysis (Alpins criteria) for postoperative cylinder, contrast sensitivity measurement, and corneal higher-order aberration profile showed no significant difference between the two groups at 3 months postoperative visit (P = 0.213, 0.514, and 0.332, respectively).
Conclusion:
Quantitative and qualitative visual outcomes with the Phorcides Analytic Software were similar to the Contoura treatment using manifest refraction.
Journal Article
Retrospective Study Comparing Topography-Guided and Wavefront-Optimized LASIK Procedures in a Single Center
2024
To compare visual outcomes of eyes that had laser refractive surgery with the Contoura Phorcides treatment plan and eyes that had laser refractive surgery with the wavefront-optimized treatment plan using the same laser.
Retrospective chart review of clinical outcomes of eyes that had either Contoura with Phorcides (CP) or wavefront-optimized (WFO) corneal refractive procedures using the Wavelight EX500 (Alcon Vision, LLC). Data were collected and compared for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, change in postoperative UDVA compared to preoperative CDVA, and change in postoperative CDVA compared to preoperative CDVA.
Total eyes included were 348, with 227 in the CP Group and 121 in the WFO Group. Post-operatively, there was a significantly higher percentage of eyes in the CP Group that were 20/16 or better compared to the WFO Group (57%, 129 eyes, and 17%, 21 eyes, respectively; p < 0.001). The percentage of eyes that gained 1 or more Snellen lines of UDVA compared to preoperative CDVA was higher in the CP Group (47%; 107 eyes) compared to the WFO Group (12%; 14 eyes), which was statistically significant (p < 0.001). Differences in refraction were statistically significant.
Topography-guided and wavefront-optimized treatment profiles both provided excellent refractive results. A higher percentage of eyes that were treated using Contoura with Phorcides achieved 20/16 or better unaided distance vision compared to eyes receiving a wavefront-optimized treatment plan.
Journal Article