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Du K, Liu E, Li N, Yuan B, Peng R, Hong J. Comparison of Femtosecond Laser Assistance and Manual Trephination in Deep Anterior Lamellar Keratoplasty in the Treatment of Keratoconus: A Meta-Analysis. Am J Ophthalmol 2023; 256:126-137. [PMID: 37553035 DOI: 10.1016/j.ajo.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/10/2023]
Abstract
PURPOSE To compare the efficacy and safety of femtosecond laser-assisted deep anterior lamellar keratoplasty (F-DALK) with those of manual-trephination DALK (M-DALK) in treating keratoconus. DESIGN Systematic review and meta-analysis. METHODS Through November 2022, we comprehensively searched PubMed, EMBASE, the Cochrane Library, and 4 Chinese databases. Studies that involved comparisons between F-DALK and M-DALK groups and that reported on relevant efficacy and/or safety parameters were included. Primary outcomes were uncorrected- and corrected-distance visual acuity and intraoperative complication rates. Secondary outcomes were spherical equivalent, topographic astigmatism, refractive cylinder, mean keratometry, endothelial cell density, suture removal time, and postoperative complication rates. These data were analyzed using Cochrane Review Manager software version 5.3. RESULTS This meta-analysis included 9 nonrandomized controlled studies involving 1713 eyes. In eyes treated with F-DALK, corrected-distance visual acuity at 1 to 6 months (weighted mean difference = -0.07 [95% confidence interval {CI} -0.10 to -0.03]; I2 = 0%; P < .001) after surgery was better and intraoperative Descemet membrane perforation occurred less often (odds ratio = 0.53 [95% CI 0.31-0.92]; I2 = 6%; P = .02) than in eyes treated with M-DALK. No clinically significant differences in other outcomes were found among the groups. CONCLUSIONS Both F-DALK and M-DALK are safe and efficacious for patients with keratoconus. Compared with M-DALK, F-DALK can provide better early visual acuity and reduce the intraoperative perforation rate, and its likely improvements to long-term visual quality and endothelial cell preservation warrant further investigation. In addition, the 2 techniques seem to be comparable regarding refractive outcomes and other complications.
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Affiliation(s)
- Kaiyue Du
- Department of Ophthalmology (K.D., E.L., B.Y., R.P., J.H.), Peking University Third Hospital, Beijing, China; Key Laboratory of Vision Loss and Restoration (K.D., E.L., B.Y., R.P., J.H.), Ministry of Education, Beijing, China
| | - Enshuo Liu
- Department of Ophthalmology (K.D., E.L., B.Y., R.P., J.H.), Peking University Third Hospital, Beijing, China; Key Laboratory of Vision Loss and Restoration (K.D., E.L., B.Y., R.P., J.H.), Ministry of Education, Beijing, China
| | - Nan Li
- Peking University Third Hospital (N.L.), Beijing, China
| | - Bowei Yuan
- Department of Ophthalmology (K.D., E.L., B.Y., R.P., J.H.), Peking University Third Hospital, Beijing, China; Key Laboratory of Vision Loss and Restoration (K.D., E.L., B.Y., R.P., J.H.), Ministry of Education, Beijing, China
| | - Rongmei Peng
- Department of Ophthalmology (K.D., E.L., B.Y., R.P., J.H.), Peking University Third Hospital, Beijing, China; Key Laboratory of Vision Loss and Restoration (K.D., E.L., B.Y., R.P., J.H.), Ministry of Education, Beijing, China
| | - Jing Hong
- Department of Ophthalmology (K.D., E.L., B.Y., R.P., J.H.), Peking University Third Hospital, Beijing, China; Key Laboratory of Vision Loss and Restoration (K.D., E.L., B.Y., R.P., J.H.), Ministry of Education, Beijing, China.
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Update on Femtosecond Laser-Enabled Keratoplasty. Cornea 2023; 42:395-403. [PMID: 36538423 DOI: 10.1097/ico.0000000000003146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 08/01/2022] [Indexed: 12/24/2022]
Abstract
ABSTRACT The application of femtosecond lasers to corneal transplantation is an intriguing proposition with many potential benefits to patients with various corneal diseases. The customized trephination pattern for donor and host matching offers many advantages regarding wound integrity and high precision of donor and recipient match at the interface, which should lead to faster healing and visual rehabilitation. Femtosecond laser-enabled keratoplasty (FLEK) is an advancement of conventional trephination penetrating keratoplasty, and in large clinical cohorts to date, there are meaningful improvements in visual outcomes and a lower risk of graft rejection. Femtosecond laser-enabled deep anterior lamellar keratoplasty (Femto-DALK) combines the advantage of a customized trephination pattern with the deep anterior lamellar keratoplasty procedure, which eliminates the risk of endothelial rejection. Furthermore, the precision of the femtosecond laser may offer additional novel approaches to lamellar keratoplasties. In time, advancements in femtosecond laser platforms will help cornea surgeons realize the added benefits and better optimize outcomes for patients, such that the cost-benefit calculus shifts toward wider accessibility for patients. Prospective randomized-controlled trials are needed to definitively determine the impact of femtosecond laser-enabled keratoplasties on long-term outcomes.
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Peng WY, Tang ZM, Lian XF, Zhou SY. Comparing the efficacy and safety of femtosecond laser-assisted vs conventional penetrating keratoplasty: a meta-analysis of comparative studies. Int Ophthalmol 2021; 41:2913-2923. [PMID: 33860436 DOI: 10.1007/s10792-021-01826-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 03/29/2021] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the safety and efficacy of femtosecond laser-assisted penetrating keratoplasty (FLAK) versus conventional penetrating keratoplasty (CPK). METHODS A literature search of PubMed, Cochrane, Embase, Web of Science, and Clinicaltrials.gov was conducted for comparative studies published from January 2007 to October 2019. Studies that involved both FLAK and CPK groups and reported on the relevant efficacy and/or safety parameters were included. The Newcastle-Ottawa quality assessment scale was used to analyse the methodological quality of these studies. Further, weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated. RESULTS From the screened articles, a total of 1991 eyes from nine comparative studies were included. FLAK was not statistically superior for twelve-month postoperative best corrected visual acuity (WMD = - 0.06; 95% CI [- 0.16, 0.04]; P = 0.22), corneal astigmatism (WMD = - 0.81; 95% CI [- 1.63, 0.01]; P = 0.05) or six-month postoperative uncorrected visual acuity (WMD = - 0.11; 95% CI [- 0.27, 0.06]; P = 0.21). There were no significant differences in corneal graft rejection rate and the graft failure between FLAK and CPK at twelve months postoperative. However, best-corrected visual acuity (BCVA) and corneal astigmatism corrected with FLAK were better than those with CPK six months postoperative after elimination of data heterogeneity. CONCLUSION Visual outcomes improvement in FLAK was better than that in CPK at six months postoperative, but not twelve months postoperative. This review recommends selecting a technique based on patients' work demands and economic burdens.
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Affiliation(s)
- Wen-Yan Peng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Zhi-Ming Tang
- Department of Rehabilitation Medicine, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510630, China
| | - Xiu-Fen Lian
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China
| | - Shi-You Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, 510060, China.
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Sioufi K, Zheleznyak L, MacRae S, Rocha KM. Femtosecond Lasers in Cornea & Refractive Surgery. Exp Eye Res 2021; 205:108477. [PMID: 33516763 DOI: 10.1016/j.exer.2021.108477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 11/18/2022]
Abstract
Since the introduction of femtosecond laser (FS) systems for corneal flap creation in laser-assisted in-situ keratomileusis there have been numerous applications for FS laser in corneal surgery. This manuscript details the utility of FS lasers in corneal surgical procedures including refractive laser surgeries, intracorneal ring segment tunnels, presbyopic treatments, and FS-assisted keratoplasty. We also review the role of FS lasers in diagnostic procedures such as two photon excitation fluorescence and second harmonic generation.
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Affiliation(s)
- Kareem Sioufi
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | | | - Scott MacRae
- Flaum Eye Institute and the Institute of Optics, University of Rochester, Rochester, NY, USA
| | - Karolinne M Rocha
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA.
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Deshmukh R, Stevenson LJ, Vajpayee RB. Laser-assisted corneal transplantation surgery. Surv Ophthalmol 2021; 66:826-837. [PMID: 33524460 DOI: 10.1016/j.survophthal.2021.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/01/2022]
Abstract
Corneal transplant surgeries have a broad range of indications with outcomes largely dependent on surgeon experience. Traditional manual techniques have certain limitations pertaining to the preparation of donor tissue and the recipient bed that might affect the predictability of visual outcomes. Use of lasers for keratoplasty procedures not only improves the repeatability and consistency of the technique, but also enables the surgeon to control the thickness and shape of the transplant tissue tailored to the specific condition. Despite the advantages, cost-effectiveness and technical know-how remain the major challenges. We discuss the various techniques of laser-assisted keratoplasties with respect to their methods, precision, and efficacy in various corneal indications.
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Affiliation(s)
- Rashmi Deshmukh
- Division of Ophthalmology and Visual Sciences, Eye ENT Centre, Queens Medical Centre, University of Nottingham, UK.
| | | | - Rasik B Vajpayee
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Vision Eye Institute, Melbourne, Australia; University of Melbourne, Australia
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Application of Femtosecond Laser in Anterior Segment Surgery. J Ophthalmol 2020; 2020:8263408. [PMID: 32351726 PMCID: PMC7171667 DOI: 10.1155/2020/8263408] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/12/2020] [Indexed: 11/24/2022] Open
Abstract
Femtosecond laser (FSL) is a near-infrared laser that can create reliable and reproducible tissue cutting with minimal damage to adjacent tissue. As the laser can also create incisions with various orientations, depths, and shapes, it is expected to be a useful tool for anterior segment surgery, such as cornea, refractive, and cataract surgery. In this review, the authors will introduce the application of FSL in various anterior segment surgeries and discuss the results of studies regarding the efficacy and safety of FSL in cornea, refractive, and cataract surgery. Experimental studies regarding the potential use of FSL will also be introduced. The studies discussed in this review suggest that FSL may be a useful tool for improving the prognosis and safety of surgeries of the anterior segment.
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Liu Y, Li X, Li W, Jiu X, Tian M. Systematic review and meta-analysis of femtosecond laser-enabled keratoplasty versus conventional penetrating keratoplasty. Eur J Ophthalmol 2020; 31:976-987. [PMID: 32223431 DOI: 10.1177/1120672120914488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE The aim of this meta-analysis is to compare femtosecond laser-enabled keratoplasty with conventional penetrating keratoplasty regarding postoperative astigmatism, visual functions, graft rejection, graft failure, and complications. METHODS Eligible studies were retrieved from five mainstream electronic databases, including PubMed, Embase, Ovid MEDLINE, Cochrane Library, and ClinicalTrial.gov. Postoperative topographic astigmatism was set as the primary outcome, and best-corrected visual acuity, spherical equivalent, endothelial cell density, graft rejection, graft failure, and complications were chosen as the secondary outcomes. Standard mean difference and risk ratio were the size effects for continuous data and binomial data, respectively. The data were pooled through either the random-effects model or the fixed-effects model based on data heterogeneity. Moreover, subgroup analyses were conducted when the heterogeneity occurred distinctly (I2 > 50%). RESULTS A total of seven comparative studies were included. The pooled standard mean difference (-0.32, 95% confidence interval: -0.74 to 0.10) showed that femtosecond laser-enabled keratoplasty was not superior over conventional penetrating keratoplasty to decrease postoperative topographic astigmatism (p = 0.14). However, best-corrected visual acuity after femtosecond laser-enabled keratoplasty was significantly better than that after conventional penetrating keratoplasty (p = 0.00, standard mean difference: -0.23, 95% confidence interval: -0.37 to -0.10). Furthermore, endothelial cell density after femtosecond laser-enabled keratoplasty was preserved significantly better (p = 0.03, standard mean difference: 0.63, 95% confidence interval: 0.07-1.20). Moreover, spherical equivalent, graft rejection, graft failure, and complications represented no distinct differences between femtosecond laser-enabled keratoplasty and conventional penetrating keratoplasty (p > 0.05). CONCLUSION Femtosecond laser-enabled keratoplasty may not be superior over conventional penetrating keratoplasty in decreasing postoperative topographic astigmatism, but might have advantages to achieve best-corrected visual acuity and endothelial cell density preservation. In addition, the two techniques seem to be comparable regarding spherical equivalent, graft rejection/failure, and complications.
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Affiliation(s)
- Yang Liu
- Department of Ophthalmology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Xiaojun Li
- Department of Ophthalmology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Wenjie Li
- Department of Ophthalmology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Xudong Jiu
- Department of Ophthalmology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Mannan Tian
- Department of Ophthalmology, The First Hospital of Lanzhou University, Lanzhou, China
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Sahay P, Stevenson LJ, Agarwal T, Sharma B, Sharma N, Vajpayee RB. Shaped corneal transplantation surgery. Br J Ophthalmol 2020; 105:9-16. [PMID: 32217546 DOI: 10.1136/bjophthalmol-2019-315754] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/22/2020] [Accepted: 03/11/2020] [Indexed: 11/04/2022]
Abstract
Since its inception in 1905, keratoplasty techniques have continuously evolved. Shaped keratoplasty procedures have allowed corneal surgeons to use complex graft-host junctions and non-circular graft designs to optimise wound strength and healing, facilitate early suture removal and expedite visual rehabilitation. While this was initially limited to penetrating procedures, shaped lamellar keratoplasty techniques have since emerged. Furthermore, the arrival of femtosecond laser has dramatically increased the range of graft designs available to surgeons, due to the technology's ability to precisely cut complex wound edges. This review describes the broad range of shaped keratoplasty grafts currently available and elaborates on their respective advantages and disadvantages in relation to conventional keratoplasty.
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Affiliation(s)
- Pranita Sahay
- Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | | | - Tushar Agarwal
- Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Bhavana Sharma
- Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, India
| | - Namrata Sharma
- Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Rasik B Vajpayee
- Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia .,University of Melbourne, Parkville, Victoria, Australia.,Vision Eye Institute, Melbourne, Victoria, Australia
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Boden KT, Schlosser R, Boden K, Januschowski K, Szurman P, Rickmann A. Novel Liquid Interface for Femtosecond Laser-Assisted Penetrating Keratoplasty. Curr Eye Res 2020; 45:1051-1057. [DOI: 10.1080/02713683.2020.1716985] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
| | | | - Katrin Boden
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
| | - Kai Januschowski
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Centre for Ophthalmology, University Eye Hospital Tuebingen, Tuebingen, Germany
| | - Peter Szurman
- Eye Clinic Sulzbach, Knappschaft Hospital Saar, Sulzbach, Germany
- Centre for Ophthalmology, University Eye Hospital Tuebingen, Tuebingen, Germany
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Trufanov SV, Budnikova EA, Rozinova VN. [Modern modifications of penetrating keratoplasty with complex operative incision]. Vestn Oftalmol 2019; 135:260-266. [PMID: 31691670 DOI: 10.17116/oftalma2019135052260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The basic principle of modern keratoplasty is selectivity, i.e. the choice of whether to replace only the affected corneal layer. However, when layer-by-layer and interlayer transplantation is not indicated, the method of choice is conventional penetrating keratoplasty. An alternative can be its modifications with complex profiles of the transplant edges and the bed, which are better justified in terms of pathogenesis. The most popular among them are mushroom, zig-zag and top-hat. These surgeries combine optical benefits of penetrating keratoplasty as they do not involve dissection of the corneal optical zone and can negate - to a certain degree - its main downsides such as low trauma tolerance of the postoperative scar, significant level of postoperative astigmatism, and increased visual rehabilitation time. Mushroom-shaped incisions can be performed manually with a femtosecond laser or a microkeratome, zig-zag incision - only with a femtosecond laser. Considering the diversity of keratoplasty modifications with complex operative incisions, further research is required for evaluation of their clinical effectiveness and analysis of postoperative complications.
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Affiliation(s)
- S V Trufanov
- Research Institute of Eye Diseases, 11A Rossolimo St., Moscow, Russian Federation, 119021
| | - E A Budnikova
- Research Institute of Eye Diseases, 11A Rossolimo St., Moscow, Russian Federation, 119021
| | - V N Rozinova
- Research Institute of Eye Diseases, 11A Rossolimo St., Moscow, Russian Federation, 119021
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Femtosecond Laser-Assisted In Situ Keratomileusis Treatment of Residual Refractive Error following Femtosecond Laser-Enabled Keratoplasty. J Ophthalmol 2019; 2019:8520183. [PMID: 31559093 PMCID: PMC6735192 DOI: 10.1155/2019/8520183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/08/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the safety and effectiveness of femtosecond laser-assisted in situ keratomileusis (LASIK) in the treatment of residual myopia and astigmatism following femtosecond laser-enabled keratoplasty (FLEK). Design Retrospective case review. Methods Chart review of all patients with prior FLEK who subsequently underwent femto-LASIK surgery after full suture removal was performed at the Gavin Herbert Eye Institute at the University of California, Irvine. A total of 14 eyes in 13 patients met this criterion, and their comprehensive examinations performed at standard intervals were reviewed. Main outcome measures include uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) expressed as the logarithm of the minimum angle of resolution (logMAR), manifest refractive astigmatism, and spherical equivalent. Results From the preoperative visit to the 3 month visit, all 14 eyes significantly improved in UDVA (logMAR, 0.93 ± 0.23 to 0.44 ± 0.32, P = 0.002) with no loss of CDVA (logMAR, 0.26 ± 0.19 to 0.18 ± 0.23, P = 0.50). All 14 eyes showed significant improvement in manifest refractive astigmatism (4.71 ± 1.77 to 2.18 ± 1.45 diopters (D), P = 0.003) and spherical equivalent (−2.57 ± 2.45 to −0.48 ± 0.83 D, P = 0.0007). There were no flap or graft complications as a result of femto-LASIK. Conclusions Our findings suggest that femto-LASIK on eyes with prior FLEK is safe and effective in improving visual acuity and reducing residual astigmatism.
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Abstract
PURPOSE OF REVIEW A survey of the recent literature of deep anterior lamellar keratoplasty using femtosecond laser technology. RECENT FINDINGS There are several recent reports in the literature assessing technique and outcomes of deep anterior lamellar keratoplasty done with a femtosecond laser trephination. Most of these reports are laboratory studies and small case series with short-term outcomes. The laser technology is expensive and may not produce better results than conventional manual techniques. However, there are several theoretical advantages to femtosecond laser incisions in deep anterior lamellar keratoplasty that should be explored, including possible increased success of Descemet's membrane separation from stroma during surgery as well as postsurgical astigmatism benefits, earlier suture removal, and increased wound strength and healing. SUMMARY Femtosecond laser trephination in the setting of DALK may improve the technique by decreasing the number of descemet's membrane ruptures and improving short-term and long-term outcomes as compared with manual techniques. However, there is no consensus on a standardized approach for wound design or postoperative management. The literature would benefit from a prospective randomized controlled trial.
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Elkamshoushy A, Gonnah R, Madi S, Beltz J. Single-piece femtosecond-assisted mushroom keratoplasty in children. J AAPOS 2019; 23:28.e1-28.e5. [PMID: 30500436 DOI: 10.1016/j.jaapos.2018.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 08/13/2018] [Accepted: 08/19/2018] [Indexed: 12/13/2022]
Abstract
PURPOSE To report outcomes of femtosecond-assisted single-piece mushroom keratoplasty for the treatment of full-thickness corneal disease in pediatric patients with healthy endothelium. METHODS Femtosecond-assisted mushroom keratoplasty was performed in 8 eyes of 8 patients (age range, 8-17 years) with central full-thickness corneal opacity. The single-piece mushroom-shaped graft consisted of a large anterior portion (9 mm in diameter; 250 μm in thickness) and a small posterior portion (6-6.5 mm). Donor and recipient corneas were prepared using the WaveLight FS200 laser (Alcon Laboratories, Fort Worth, TX). The donor cornea was oversized by 0.2 mm. Outcome measures were best spectacle-corrected visual acuity, spectacle refraction, topographic astigmatism, endothelial cell density, graft rejection, and graft failure at 1, 3, 6, and 12 months. RESULTS Mean best spectacle-corrected visual acuity at 1, 3, 6, and 12 months was 0.28, 0.16, 0.13, and 0.10 logMAR; all patients achieved logMAR of at least 0.4 at 1, 3, 6, and 12 months. The mean refractive cylinder was 2.6 D, and mean endothelial cell loss was 13.3% at 12 months postoperatively. Two eyes had immunologic rejection episodes that were reversed with topical steroids. All corneas remained clear at final follow-up. CONCLUSIONS Femtosecond-assisted mushroom keratoplasty is a viable surgical option for eyes of older pediatric patients with full-thickness corneal stromal disease and healthy endothelium. Mushroom keratoplasty combines the refractive advantage of a large keratoplasty with the immunologic advantage of a small keratoplasty. Single-piece femtosecond-assisted mushroom keratoplasty may have a mechanical advantage over regular penetrating keratoplasty.
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Affiliation(s)
- Amr Elkamshoushy
- Ophthalmology Department, Alexandria University, Alexandria, Egypt
| | - Reem Gonnah
- Ophthalmology Department, Alexandria University, Alexandria, Egypt
| | - Silvana Madi
- Ophthalmology Department, Alexandria University, Alexandria, Egypt.
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Abstract
PURPOSE To report long-term visual and astigmatism outcomes in cases of zig-zag femtosecond laser-enabled penetrating keratoplasty (FLEK). METHODS Retrospective review. Three hundred thirty-five eyes of 287 patients underwent (FLEK) with a zig-zag incision pattern. Patients were assessed preoperatively and underwent postoperative comprehensive examinations at standard intervals of 1, 3, 6, 9, and 12 months, and 6 months thereafter. Postoperative uncorrected distance visual acuity and spectacle-corrected distance visual acuity and manifest and topographical (Mrx cyl and Topo cyl) astigmatism were compared with preoperative values. RESULTS Three hundred thirty-five eyes received FLEK with zig-zag configuration. Data are presented for the last recorded visit before any refractive procedure. Sutures were removed in 202 of 335 eyes at an average time to removal of 1.3 ± 1.1 years, and a mean follow-up period of 2.9 ± 2.1 years (range 0-10 years). After full suture removal, mean uncorrected distance visual acuity and spectacle-corrected distance visual acuity were logarithm of the minimum angle of resolution 0.84 (Snellen 20/138) ± 0.55 and 0.33 (Snellen 20/42) ± 0.33, respectively. Mean Mrx cyl and Topo cyl of these groups were 3.38 ± 2.22 and 4.77 ± 3.15, respectively. Of the total number of grafts, the rate of graft rejections was 14.0%, and the failure rate was 5.6%. CONCLUSIONS The femtosecond laser-generated zig-zag-shaped incision results in lower manifest and topographical astigmatism than the reported average for conventional penetrating keratoplasty. Graft rejection and failure rates are similar to published data for conventional penetrating keratoplasty.
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Zhang C, Liu L, Tang M, Li Y, Chamberlain W, Huang D. Laboratory Evaluation of Femtosecond Laser Lamellar Cuts in Gamma-Irradiated Corneas. Cornea 2016; 34:1499-503. [PMID: 26382890 DOI: 10.1097/ico.0000000000000614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To evaluate the stromal interface quality after femtosecond laser full lamellar cuts in gamma-irradiated corneas (VisionGraft sterile cornea) and to determine the limits of the cut depth using the VisionGraft as donor corneas for laser-assisted lamellar anterior keratoplasty. METHODS Fourteen VisionGraft corneas underwent full lamellar cuts using the femtosecond laser. The percent cut depth was 17% to 21% (100 μm, n = 2), 31% to 35% (n = 3), 38% to 40% (n = 3), 45% to 48% (n = 3), and 50% (n = 3) of the total stromal thickness (not including the epithelium). The cap and stromal bed surfaces were imaged with a scanning electron microscope. The quality of cut surfaces was graded by 2 masked observers based on two indices: ridge and roughness. Ridge grading indicated macroscopic irregularity. Roughness grading indicated microscopic irregularity. The grading was done on a subjective integer scale of 1 to 5 (1 = best and 5 = worst), which was used in a previous study of cut quality in fresh corneas. RESULTS The ridge grading ranged from 1.5 for the shallowest cut to 2.2 for the deepest cut and weakly (r = 0.279) but significantly (P = 0.037) correlated with the percent cut depth. The roughness grading ranged from 2.63 to 2.56 and showed no trend with the percent cut depth (r = 0.006, P = 0.968). CONCLUSIONS Compared with previously published results of fresh corneas, in which ridge grading exceeded 3 for cuts deeper than 31%, cut quality was better for the VisionGraft. Even at depths up to 48% of the total stromal thickness, ridge grading was not worse than shallow cuts. Thus, gamma-irradiated corneas could provide a smoother interface than do fresh eye bank corneas for laser-assisted lamellar anterior keratoplasty.
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Affiliation(s)
- Chenxing Zhang
- *Center for Ophthalmic Optics and Lasers, Casey Eye Institute, Portland, OR; †Department of Ophthalmology, Oregon Health and Science University, Portland, OR; ‡Department of Ophthalmology, Southwest Eye Hospital, Third Military Medical University, Chongqing, China; and §Department of Ophthalmology, Peking Union Medical College Hospital, Beijing, China
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Espandar L, Mandell JB, Niknam S. Femtosecond laser-assisted decagonal deep anterior lamellar keratoplasty. Can J Ophthalmol 2016; 51:67-70. [DOI: 10.1016/j.jcjo.2015.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Revised: 12/05/2015] [Accepted: 12/07/2015] [Indexed: 11/29/2022]
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Comparison of Long-Term Outcomes of Femtosecond Laser-Assisted Keratoplasty with Conventional Keratoplasty. Cornea 2016; 35:293-8. [DOI: 10.1097/ico.0000000000000739] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Excimer versus Femtosecond Laser Assisted Penetrating Keratoplasty in Keratoconus and Fuchs Dystrophy: Intraoperative Pitfalls. J Ophthalmol 2015; 2015:645830. [PMID: 26483974 PMCID: PMC4592921 DOI: 10.1155/2015/645830] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/02/2015] [Accepted: 05/13/2015] [Indexed: 11/18/2022] Open
Abstract
Purpose. To assess the intraoperative results comparing two non-mechanical laser assisted penetrating keratoplasty approaches in keratoconus and Fuchs dystrophy. Patients and Methods. 68 patients (age 18 to 87 years) with keratoconus or Fuchs dystrophy were randomly distributed to 4 groups. 35 eyes with keratoconus and 33 eyes with Fuchs dystrophy were treated with either excimer laser ([Exc] groups I and II) or femtosecond laser-assisted ([FLAK] groups III and IV) penetrating keratoplasty. Main intraoperative outcome measures included intraoperative decentration, need for additional interrupted sutures, alignment of orientation markers, and intraocular positive pressure (vis a tergo). Results. Intraoperative recipient decentration occurred in 4 eyes of groups III/IV but in none of groups I/II. Additional interrupted sutures were not necessary in groups I/II but in 5 eyes of groups III/IV. Orientation markers were all aligned in groups I/II but were partly misaligned in 8 eyes of groups III/IV. Intraocular positive pressure grade was recognized in 12 eyes of groups I/II and in 19 eyes of groups III/IV. In particular, in group III, severe vis a tergo occurred in 8 eyes. Conclusions. Intraoperative decentration, misalignment of the donor in the recipient bed, and need for additional interrupted sutures as well as high percentage of severe intraocular positive pressure were predominantly present in the femtosecond laser in keratoconus eyes.
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Zhang C, Bald M, Tang M, Li Y, Huang D. Interface quality of different corneal lamellar-cut depths for femtosecond laser-assisted lamellar anterior keratoplasty. J Cataract Refract Surg 2015; 41:827-35. [PMID: 25747165 DOI: 10.1016/j.jcrs.2014.08.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 07/31/2014] [Accepted: 08/19/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE To evaluate the interface quality of different corneal lamellar-cut depths with the femtosecond laser and determine a feasible range of depth for femtosecond laser-assisted lamellar anterior keratoplasty. SETTING Casey Eye Institute, Portland, Oregon, USA. DESIGN Experimental study. METHODS Full lamellar cuts were made on 20 deepithelialized human cadaver corneas using the femtosecond laser. The cut depth was 17% to 21% (100 μm), 31%, 35%, 38% to 40%, and 45% to 48% of the central stromal thickness. Scanning electron microscopy images of the cap and bed surfaces were subjectively graded for ridge and roughness using a scale of 1 to 5 (1 = best). The graft-host match was evaluated by photography and optical coherence tomography in a simulated procedure. RESULTS The ridge score was correlated with the cut depth (P = .0078, R = 0.58) and better correlated with the percentage cut depth (P = .00024, R = 0.73). The shallowest cuts had the fewest ridges (score 1.25). The 31% cut depth produced significantly fewer ridges (score 2.15) than deeper cuts. The roughness score ranged from 2.19 to 3.08 for various depths. A simulated procedure using a 100 μm host cut and a 177 μm (31%) graft had a smooth interface and flush anterior junction using an inverted side-cut design. CONCLUSIONS The femtosecond laser produced more ridges in deeper lamellar cuts. A depth setting of 31% stromal thickness might produce adequate surface quality for femtosecond laser-assisted lamellar anterior keratoplasty. The inverted side-cut design produced good edge apposition even when the graft was thicker than the host lamellar-cut depth. FINANCIAL DISCLOSURE Proprietary or commercial disclosures are listed after the references.
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Affiliation(s)
- Chenxing Zhang
- From the Center for Ophthalmic Optics & Lasers (Zhang, Bald, Tang, Li, Huang), Casey Eye Institute and Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA; the Southwest Eye Hospital (Zhang), Third Military Medical University, Chongqing, China
| | - Matthew Bald
- From the Center for Ophthalmic Optics & Lasers (Zhang, Bald, Tang, Li, Huang), Casey Eye Institute and Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA; the Southwest Eye Hospital (Zhang), Third Military Medical University, Chongqing, China
| | - Maolong Tang
- From the Center for Ophthalmic Optics & Lasers (Zhang, Bald, Tang, Li, Huang), Casey Eye Institute and Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA; the Southwest Eye Hospital (Zhang), Third Military Medical University, Chongqing, China
| | - Yan Li
- From the Center for Ophthalmic Optics & Lasers (Zhang, Bald, Tang, Li, Huang), Casey Eye Institute and Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA; the Southwest Eye Hospital (Zhang), Third Military Medical University, Chongqing, China
| | - David Huang
- From the Center for Ophthalmic Optics & Lasers (Zhang, Bald, Tang, Li, Huang), Casey Eye Institute and Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA; the Southwest Eye Hospital (Zhang), Third Military Medical University, Chongqing, China.
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Outcome of "mushroom" pattern femtosecond laser-assisted keratoplasty versus conventional penetrating keratoplasty in patients with keratoconus. Cornea 2014; 33:481-5. [PMID: 24619167 DOI: 10.1097/ico.0000000000000080] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The aim of this study was to compare the outcomes of "mushroom" femtosecond laser-enabled keratoplasty (M-FLEK) with those of conventional penetrating keratoplasty (PKP) in eyes with keratoconus. The femtosecond laser-enabled "mushroom" pattern keratoplasty technique results in less postoperative astigmatism and higher endothelial cell counts compared with conventional PKP in patients with keratoconus. METHODS This was a nonrandomized retrospective, single private center clinical study. Between March 2010 and April 2012, 26 eyes underwent M-FLEK and 33 eyes underwent conventional PKP. Data on preoperative and postoperative manifest refraction, uncorrected visual acuity and best-corrected visual acuity (BCVA), endothelial cell counts, vector analysis, and complications were retrieved and analyzed. RESULTS At 12 months of follow-up, the mean logMAR BCVA was 0.31 ± 0.55 in the M-FLEK group and 0.32 ± 0.21 in the PKP group (P = 0.91). The mean spherical equivalent was similar between the groups. The mean manifest cylinder was significantly lower in the M-FLEK group (-2.84 ± 1.08 diopters) than in the PKP group (-3.93 ± 2.26 diopters; P = 0.03). There was a smaller mean endothelial cell loss in the M-FLEK group compared with the PKP group (32.1% vs 38.7%, respectively, P = 0.17) 1 year postoperatively. The complication rates were similar for both groups. CONCLUSIONS M-FLEK appears to be a safe procedure that results in less astigmatism and a trend toward higher endothelial cell counts compared with conventional PKP, with similar postoperative BCVA.
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Kamiya K, Kobashi H, Shimizu K, Igarashi A. Clinical outcomes of penetrating keratoplasty performed with the VisuMax femtosecond laser system and comparison with conventional penetrating keratoplasty. PLoS One 2014; 9:e105464. [PMID: 25126741 PMCID: PMC4134291 DOI: 10.1371/journal.pone.0105464] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/24/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To assess the clinical outcomes of femtosecond laser-assisted keratoplasty (FLAK) using the VisuMax femtosecond laser system, and to compare them with those of conventional penetrating keratoplasty (PK). METHODS We retrospectively examined 20 eyes of 20 consecutive patients undergoing FLAK and 20 eyes of 20 age- and diagnosis-matched patients undergoing conventional PK. We quantitatively assessed corneal astigmatism, refractive astigmatism, and corrected visual acuity, 1, 3, and 6 months postoperatively, and endothelial cell density 6 months postoperatively. RESULTS Corneal and refractive astigmatism after FLAK were significantly lower after FLAK than that after conventional PK at 3 and 6 months postoperatively (p = 0.04 and p = 0.03, respectively, Mann-Whitney U test). FLAK provided significantly faster visual recovery than conventional PK at 1 month postoperatively (p = 0.02), but not at 3 and 6 months postoperatively (p = 0.52 and p = 0.80, respectively). We found no significant differences in the change in endothelial cell density between the two groups (p = 0.30). CONCLUSIONS FLAK using the VisuMax femtosecond laser system induces significantly less corneal and refractive astigmatism than conventional PK, and provides significantly faster visual recovery in the early postoperative period, possibly because the geometry of the donor-recipient matching is more physiological and requires less tight sutures. It is suggested that FLAK has advantages over conventional PK, in terms of astigmatism and fast visual recovery.
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Affiliation(s)
- Kazutaka Kamiya
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
- * E-mail:
| | - Hidenaga Kobashi
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
| | - Kimiya Shimizu
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
| | - Akihito Igarashi
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan
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Nada O, Marian A, Tran-Khanh N, Buschmann M, Podtetenev M, Vidal F, Costantino S, Brunette I. Effect of corneal hydration on the quality of the femtosecond laser anterior lamellar cut. PLoS One 2014; 9:e98852. [PMID: 24911840 PMCID: PMC4049624 DOI: 10.1371/journal.pone.0098852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 05/08/2014] [Indexed: 11/19/2022] Open
Abstract
The goal of this study was to assess the effect of corneal hydration on the quality of the femtosecond laser (FSL) anterior lamellar cut. The Visumax FSL was used to dissect an 8-mm-diameter corneal flap in 22 eye bank corneas showing various levels of hydration. The intended ablation depth was 220 µm in all eyes, which corresponded to the maximal depth available with this laser. After the cut, the achieved ablation depth was measured using optical coherence tomography images, flap separability was assessed by measuring the mean force generated to detach the flap, and stromal bed roughness was assessed by measuring the Haralick contrast level on the 1000× scanning electron microscopy images of the ablated surfaces. The preoperative central corneal thickness ranged from 547 to 1104 µm (mean ± SEM: 833 ± 30 µm). A negative correlation was found between the level of corneal hydration and the ablation depth measured in the mid-peripheral cornea (r = -0.626, p = 0.003), the ablation being more superficial in more edematous corneas. The Haralick contrast also tended to increase as a function of corneal hydration (r = 0.416, p = 0.061), suggesting that laser ablation in edematous corneas results in rougher stromal surfaces. These results support the hypothesis that the quality of the FSL lamellar cut decreases as the level of corneal hydration increases. Although FSL is still considered in the field as the tool of the future for corneal dissection, a better understanding of the limits of this tool will be needed before it can replace manual or automated stromal dissection techniques in hydrated corneas.
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Affiliation(s)
- Ossama Nada
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Québec, Canada
- Ain Shams University, Cairo, Egypt
| | - Anca Marian
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Québec, Canada
| | - Nicolas Tran-Khanh
- Biomedical and Chemical Engineering and Groupe de Recherche en Sciences et Technologies Biomédicales, École Polytechnique, Montreal, Québec, Canada
| | - Michael Buschmann
- Biomedical and Chemical Engineering and Groupe de Recherche en Sciences et Technologies Biomédicales, École Polytechnique, Montreal, Québec, Canada
| | - Michel Podtetenev
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Québec, Canada
- Department of Ophthalmology, University of Montreal, Montreal, Québec, Canada
- Focus Vision Clinic, Verdun, Québec, Canada
| | - François Vidal
- Institut National de la Recherche Scientifique – Centre Énergie Matériaux Télécommunications, Varennes, Québec, Canada
| | - Santiago Costantino
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Québec, Canada
- Department of Ophthalmology, University of Montreal, Montreal, Québec, Canada
| | - Isabelle Brunette
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Québec, Canada
- Department of Ophthalmology, University of Montreal, Montreal, Québec, Canada
- * E-mail:
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Shivanna Y, Nagaraja H, Kugar T, Shetty R. Femtosecond laser enabled keratoplasty for advanced keratoconus. Indian J Ophthalmol 2014; 61:469-72. [PMID: 23925340 PMCID: PMC3775090 DOI: 10.4103/0301-4738.116060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose: To assess the efficacy and advantages of femtosecond laser enabled keratoplasty (FLEK) over conventional penetrating keratoplasty (PKP) in advanced keratoconus. Materials and Methods: Detailed review of literature of published randomized controlled trials of operative techniques in PKP and FLEK. Results: Fifteen studies were identified, analyzed, and compared with our outcome. FLEK was found to have better outcome in view of better and earlier stabilization uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and better refractive outcomes with low astigmatism as compared with conventional PKP. Wound healing also was noticed to be earlier, enabling early suture removal in FLEK. Conclusions: Studies relating to FLEK have shown better results than conventional PKP, however further studies are needed to assess the safety and intraoperative complications of the procedure.
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Affiliation(s)
- Yathish Shivanna
- Narayana Nethralaya, Department of Cornea and Refractive Services, Bangalore, Karnataka, India
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Shehadeh Mashor R, Bahar I, Rootman DB, Kumar NL, Singal N, Slomovic AR, Rootman DS. Zig Zag versus Top Hat configuration in IntraLase-enabled penetrating keratoplasty. Br J Ophthalmol 2013; 98:756-9. [PMID: 24081500 DOI: 10.1136/bjophthalmol-2012-303049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To compare the outcomes with IntraLase-enabled keratoplasty using (IEK) Top Hat (TH) versus Zig Zag (ZZ) configuration. METHODS Retrospective comparative series of 24 eyes that underwent TH and 10 eyes that underwent ZZ IEK. RESULTS There were no significant differences in LogMar Best-spectacle corrected visual acuity (TH- IEK=0.3; ZZ-IEK=0.18, p=0.18), spherical equivalent (TH-IEK=-3.55±3.7 dioptres (D); ZZ-IEK=-2.69±4.85 D, p=0.60), manifest cylinder (TH- IEK=3.79±2.43 D; ZZ- IEK=4.61±3.29 D, p=0.45), topographic astigmatism (TH-IEK=3.67±2.34 D; ZZ-IEK=4.26±1.1 D, p=0.63), total higher-order aberrations (TH- IEK=8.26±3.53; ZZ-IEK=8.1±4.71, P=0.92), endothelial cell density change from baseline (TH- IEK= -41.55%±15.86; ZZ-IEK=-25.45%±30.66, p=0.22) or time to suture removal in months (TH- IEK=7.48±4.07; ZZ- IEK=6.93±2.71, p=0.75). There was no difference in requirements for astigmatic keratectomy (TH-IEK=54.2%±13; ZZ-IEK=50%±5, OR=1.18) or complications (TH-IEK=25%±6; ZZ-IEK=30%±3, OR=0.78). CONCLUSIONS TH-IEK and ZZ-IEK have comparable visual and refractive outcomes, wound healing and endothelial cell counts at 1-year.
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Affiliation(s)
- Raneen Shehadeh Mashor
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada Departfment of Ophthalmology, Bnai Zion Medical Center, Technion, Haifa, Israel
| | - Irit Bahar
- Department of Ophthalmology, Rabin Medical Center, Petach, Tiqva, Israel
| | - Dan B Rootman
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Nikhil L Kumar
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Neera Singal
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Allan R Slomovic
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - David S Rootman
- Department of Ophthalmology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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Abstract
PURPOSE OF REVIEW To review the literature for recent advancements in the femtosecond laser technology with regard to its applications in corneal transplantation and eye banking. RECENT FINDINGS Advancements in corneal surgery have encouraged the use of disease-specific corneal subcomponents, utilized in procedures such as anterior-lamellar keratoplasty and endothelial keratoplasty, instead of traditional transplant procedures to minimize adverse effects of penetrating keratoplasty. Femtosecond laser microkeratomes can precisely create flaps for such transplant procedures, achieve better wound stability, and promote healing by shaped wound configurations. Laser microkeratomes have been compared to traditional mechanical microkeratomes for keratoplasty procedures from various aspects and are superior in some aspects and offer unique capabilities. SUMMARY Femtosecond laser applications in eye banking include preparation of donor and recipient corneas for use in penetrating keratoplasty, anterior-lamellar keratoplasty, and endothelial keratoplasty. Advantages of femtosecond laser microkeratomes include higher precision of the cut, ability to achieve thinner flaps, and wound configurations that allow greater wound stability, shorter recovery time, and less postoperative pain. However, cost and availability at the eye-bank level may hinder widespread and immediate application.
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Abstract
BACKGROUND The purpose of this report is to describe the initial outcomes of femtosecond laser-assisted penetrating keratoplasty. METHODS This retrospective surgical case series consisted of 10 eyes from 10 patients undergoing penetrating keratoplasty at a tertiary center. Femtosecond laser was used to perform a zig-square incision on the donor cornea with matched dimensions on the recipient cornea. Outcomes measured included: unaided visual acuity and best spectacle-corrected visual acuity preoperatively and at one, 3, 6, and 12 months postoperatively; manifest refractive and topographic astigmatism at 3, 6, and 12 months postoperatively; and endothelial cell density loss, calculated at the end of the one-year follow-up period. RESULTS At one-year follow-up, there was an improvement in unaided visual acuity from a mean preoperative logMAR of 1.67 to 0.44, and best spectacle-corrected visual acuity from a mean preoperative logMAR of 1.33 to 0.13. By postoperative month 3, mean manifest refractive and topographic astigmatism was 2.31 ± 1.41 D and 2.59 ± 1.57 D, respectively. The mean reduction in endothelial cell density was 20.7% after one year of follow-up. CONCLUSION Femtosecond laser-assisted penetrating keratoplasty provided a good visual outcome and early visual rehabilitation due to precise graft-host alignment and reduced astigmatism in the early postoperative months.
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Gaster RN, Dumitrascu O, Rabinowitz YS. Penetrating keratoplasty using femtosecond laser-enabled keratoplasty with zig-zag incisions versus a mechanical trephine in patients with keratoconus. Br J Ophthalmol 2012; 96:1195-9. [PMID: 22790433 PMCID: PMC3598602 DOI: 10.1136/bjophthalmol-2012-301662] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS This paper will compare the visual outcomes of two different penetrating keratoplasty (PKP) techniques in patients with keratoconus. It is a retrospective comparative surgical case series of 116 keratoconus patients (137 eyes) who had PKP at the Cornea Eye Institute, Beverly Hills, California, USA. METHODS 56 keratoconus patients (66 eyes) underwent femtosecond laser-enabled keratoplasty (FLEK) with a zig-zag incision configuration. Their visual parameters were compared with those of 60 patients (71 eyes) who had traditional blade mechanical trephination PKP. The range of follow-up was between 3 and 6 months. The main outcome measures included uncorrected visual acuity and best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent and topographically determined astigmatism. RESULTS BSCVA was significantly better as early as 3 months postoperatively (p=0.001) in the FLEK group. Visual recovery to 20/40 after 3 months was significantly better in the FLEK group (p<0.001). Topographic astigmatism was lower in the FLEK group, but the difference between the two groups reached significance only at 3 months of follow-up (p=0.001). Postoperative complications noted were not different between the two groups. CONCLUSIONS Faster visual recovery and better long-term outcomes were observed in keratoconus patients who had FLEK compared with those who had the mechanical PKP procedure with 6 months of postoperative follow-up.
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Birnbaum F, Wiggermann A, Maier PC, Böhringer D, Reinhard T. Clinical results of 123 femtosecond laser-assisted penetrating keratoplasties. Graefes Arch Clin Exp Ophthalmol 2012; 251:95-103. [PMID: 22573413 DOI: 10.1007/s00417-012-2054-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 04/01/2012] [Accepted: 04/23/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Postoperative astigmatism following penetrating keratoplasty is a major problem after corneal transplantation. The main goal of new trephination techniques such as femtosecond laser or excimer-laser trephination is to improve refractive and visual outcomes. The femtosecond laser technique makes profiled corneal trephinations such as the top hat or mushroom profile possible. We present the postoperative outcome of femtosecond laser-assisted penetrating keratoplasties. METHODS We performed 123 femtosecond laser-assisted penetrating keratoplasties in 119 patients. The main outcome measures were intraoperative specifics, astigmatism, and irregularity in Orbscan corneal topography, as well as the occurrence of immune reactions and side-effects. RESULTS All sutures have been removed in 49 of these 123 eyes. Their mean follow-up was 13.9 ± 4.5 months. Time to complete suture removal (n = 49) was 12.0 ± 3.7 months in the mushroom group and 9.8 ± 2.1 months in the top hat group. Mean astigmatism in Orbscan topography was 6.4 ± 3.0 diopters in the mushroom and 5.8 ± 4.6 diopters in the top hat group (all sutures out). CONCLUSIONS Femtosecond laser-assisted penetrating keratoplasty is a safe surgical technique. Due to the steps in profiled trephinations, the wound area is larger and theoretically the wound healing is, thus, faster and more stable. Complete suture removal is possible at an earlier time point compared to conventional penetrating keratoplasty. However, refractive results are not superior to those following conventional trephination.
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Affiliation(s)
- Florian Birnbaum
- Eye Hospital, Klinikum Bremen-Mitte gGmbH, St.-Jürgenstr. 1, 28177 Bremen, Germany.
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Shtein RM, Kelley KH, Musch DC, Sugar A, Mian SI. In vivo confocal microscopic evaluation of corneal wound healing after femtosecond laser-assisted keratoplasty. Ophthalmic Surg Lasers Imaging Retina 2012; 43:205-13. [PMID: 22329795 DOI: 10.3928/15428877-20120209-01] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 01/06/2012] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To evaluate corneal wound healing after femtosecond laser-assisted keratoplasty (FLAK) using in vivo confocal microscopy (IVCM). PATIENTS AND METHODS Prospective, interventional, consecutive case series of 17 eyes after mushroom-shaped FLAK. IVCM was performed preoperatively and at 1, 3, 6, and 12 months postoperatively to assess wound healing. RESULTS Mean keratocyte activation grade increased from preoperative levels to 1 month postoperatively in both the central (0.41 ± 0.62 to 1.73 ± 1.03) and peripheral (0.47 ± 0.52 to 1.57 ± 1.09) cornea, then gradually decreased through 12 months. Dendritic cells increased from preoperatively to 1 month postoperatively in both the central (0.71 ± 0.83 to 1.33 ± 0.98) and peripheral (0.79 ± 0.70 to 1.42 ± 0.90) cornea, then gradually decreased until 6 months postoperatively. Stromal reinnervation was 1 month postoperatively in 8 patients (50%). By 12 months, sub-epithelial nerves were observed centrally in 5 patients (45.5%). CONCLUSION IVCM after FLAK shows an initial increase in keratocyte activation and dendritic cells that decrease over time. Corneal reinnervation is seen as early as 1 month postoperatively.
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Affiliation(s)
- Roni M Shtein
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, Ann Arbor, MI 48105, USA.
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Femtosecond laser photodisruptive effects on the posterior human corneal stroma investigated with atomic force microscopy. Eur J Ophthalmol 2012; 22 Suppl 7:S89-97. [PMID: 22267457 DOI: 10.5301/ejo.5000113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE To analyze the effects of femtosecond laser pulses on the posterior human corneal stroma with atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM). METHODS A femtosecond laser (IntraLase iFS, Abbott, USA) was programmed to create a full posterior lamellar dissection in 9 human corneal tissues, using 3 different pulse energies (1.00 µJ, 0.75 µJ, and 0.50 µJ). Three corneal tissues were prepared in a similar fashion using a mechanical microkeratome (Moria Evolution 3, Moria, France). Six corneal tissues received an 8.00-mm diameter full cylindrical resection using either the femtosecond laser or the Barron trephine (Katena Products Inc., USA). The posterior corneal lenticules were first examined at AFM (Autoprobe CP, Veeco, USA). Both the posterior lenticules and the trephined corneal samples were scanned by ESEM (FEI Quanta 400, USA). RESULTS Granules and crater-like features were observed on the stromal interface of all the laser dissected tissues, likely due to a secondary thermal effect of femtosecond laser dissection. Collagen fibers were seen only on samples treated with the 0.50 µJ pulse energy. Images of an even stromal surface were observed on the posterior stroma of mechanically dissected corneal samples. CONCLUSIONS Mechanical and thermal effects, induced by femtosecond laser pulses on the human corneal stroma, were seen with AFM. Surface regularity of the photodisrupted stroma was inversely and non-linearly related to the pulse energy. The femtosecond laser provided high surface quality for lamellar resection of the posterior stroma comparable to those provided by mechanical devices.
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Investigation of femtosecond laser--enabled keratoplasty wound geometry using optical coherence tomography. Cornea 2011; 30:889-94. [PMID: 21389851 DOI: 10.1097/ico.0b013e3182041fd3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To measure the wound geometry after femtosecond laser-enabled keratoplasty (FLEK) using optical coherence tomography (OCT). DESIGN Prospective nonrandomized clinical study and laboratory study. PARTICIPANTS Patients who were candidates for penetrating keratoplasty at an academic referral center. METHODS Wound architecture was measured and analyzed by OCT in 8 eyes of 8 consecutive patients who underwent FLEK. Femtosecond laser lamellar cuts were performed on 3 eye bank corneas, and the wound diameters were measured by OCT. RESULTS Sutures were completely removed on average at 1 month per decade of age after surgery. No cases of wound dehiscence were noted, and graft-host tissue apposition appeared excellent on OCT. The mean spectacle-corrected visual acuity 1 month after suture removal was 20/35, and mean astigmatism was 5.0 diopters by manifest refraction and 8.7 diopters by computerized topography. The measured graft diameter was smaller than the laser setting by 2.5% (P = 0.007). The cut diameters of the eye bank corneas were also slightly smaller than the laser setting. CONCLUSIONS FLEK offers benefits of rapid wound healing and predictable wound geometry. The measured wound geometry agreed well with laser setting other than a small systematic deviation that could be explained by the mechanics of corneal applanation during the laser cut. OCT is a useful tool to measure the actual graft diameter after FLEK.
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Outcomes of deep anterior lamellar keratoplasty versus intralase enabled penetrating keratoplasty in keratoconus. Can J Ophthalmol 2011; 46:403-7. [DOI: 10.1016/j.jcjo.2011.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 03/17/2011] [Accepted: 05/16/2011] [Indexed: 11/23/2022]
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The intrastromal corneal ring in penetrating keratoplasty-long-term results of a prospective randomized study. Cornea 2011; 30:780-3. [PMID: 21436688 DOI: 10.1097/ico.0b013e318206caa9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Postoperative astigmatism after penetrating keratoplasty is a major problem in corneal transplantation. The purpose of this prospective randomized study was to evaluate the efficacy and safety of an intrastromal corneal ring after penetrating keratoplasty. METHODS Twenty patients were included, 10 of whom received an intracorneal ring (group 1) and 10 who did not (group 2, control group). Astigmatism in Orbscan corneal topography, occurrence of immune reactions, and occurrence of side effects were this study's main outcome criteria. RESULTS Mean follow-up time was 27.6 ± 5.3 months. Mean astigmatism (Orbscan) was 4.4 diopters in group 1 and 4.4 diopters in group 2 (P = 0.695). Spontaneous suture rupture occurred in 5 patients with corneal ring but in none of those in the control group. We observed 3 immune reactions in 3 patients with corneal ring, whereas group 2 experienced no rejection (P < 0.05). Endothelial cell loss was 15.1% in the group with the ring and 8.7% in the control group. That difference was not statistically significant (P = 0.146). CONCLUSIONS The use of the intrastromal corneal ring after penetrating keratoplasty caused no reduction in postoperative astigmatism. However, its use was statistically significantly associated with adverse events.
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Birnbaum F, Maier P, Reinhard T. Perspektiven der Femtosekundenlaser-assistierten Keratoplastik. Ophthalmologe 2011; 108:807-16. [PMID: 21909868 DOI: 10.1007/s00347-011-2334-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Moshirfar M, Neuffer MC, Kinard K, Lependu MT, Sikder S. Femtosecond-assisted preparation of donor tissue for Boston type 1 keratoprosthesis. Clin Ophthalmol 2011; 5:1017-20. [PMID: 21845027 PMCID: PMC3151563 DOI: 10.2147/opth.s22847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Indexed: 11/29/2022] Open
Abstract
We describe a technique for femtosecond laser-assisted preparation of donor tissue for Boston type 1 keratoprosthesis to provide accurate double punching of the donor tissue for optimized alignment in the visual axis. The technique was reproducibly performed in four donor corneas mounted in an artificial anterior chamber. This technique can provide optically centered donor tissue with smooth trephinated edges.
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Affiliation(s)
- Majid Moshirfar
- John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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Rocha G, Butler M, Butler A, Hackett JM. Femtosecond-UVA-riboflavin (FUR) cross-linking approach to penetrating keratoplasty and anterior lamellar keratoplasty. Saudi J Ophthalmol 2011; 25:261-7. [PMID: 23960934 DOI: 10.1016/j.sjopt.2011.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 04/22/2011] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To introduce femtosecond laser wound design combined with riboflavin/ultraviolet light-A (UVA) collagen cross-linking at the wound for penetrating (PKP) and anterior lamellar keratoplasty (ALK). Primary outcomes were intraocular pressure (IOP in mmHg) at burst point for the PKP group, and tensile strength (kPa) until dehiscence for the ALK group. METHODS Human corneoscleral rims (N = 20) were mounted on artificial anterior chambers. PKP specimens underwent FUR, femtosecond laser-cut without cross-linking, or conventional corneal transplantation. PKP maximum burst IOP with progressive suture removal was assessed by a digital manometer, in triplicate and by three observers. ALK involved whole human globes (N = 10) divided into three groups using a 200-micron, 8 mm diameter donor lenticule, with or without cross-linking. Cross-linked specimens were exposed to UVA light (3 mW/cm(2) irradiance, 3.4 J, 370 nm wavelength) for 30 min with 0.1% riboflavin (20% Dextran) applied every 2-min. ALK tensile strength was determined using a digital tensiometer. RESULTS In PKP, burst IOP was 31.32 mmHg greater for corneas that underwent the UVA-riboflavin treatment than for those that did not (p < 0.05). There was no significant relationship (p = 0.719) established between cut design (femtosecond versus conventional). On multivariate analysis, there was a mean of 15.82 mmHg higher sustainable pressure for each stabilization suture present (p < 0.0001). In ALK, specimens comprised of human donor and human recipient tissue combined with UVA-riboflavin therapy experienced the greatest level of adhesion strength (954.7 ± 290.4 kPa) as shown by the force required to separate the tissues, and compared to non-cross-linked specimens. Electron microscopy of ALK specimens showed non-fused and fused longitudinal cross-linked collagen fibers as well as bridges, densities, attachment plaques and primitive plasmalemmal densities. CONCLUSIONS Cross-linking effects of the FUR technique enable a stronger graft-recipient adhesion compared to conventional penetrating and anterior lamellar keratoplasty. Electron microscopy enabled visualization of cross-linked interface and potential bonding. The FUR approach may further lead to sutureless transplantation techniques in the future. SETTING/VENUE ImagePlus Laser Eye Centre, Winnipeg, and University of Ottawa Eye Institute, Ottawa, Canada.
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Affiliation(s)
- Guillermo Rocha
- GRMC Vision Centre, Image Plus Laser Eye Centre, University of Manitoba, Winnipeg, Manitoba, Canada ; Department of Ophthalmology, University of Ottawa Eye Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
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Femtosecond laser-assisted keratoplasty. Am J Ophthalmol 2011; 151:189-91. [PMID: 21251491 DOI: 10.1016/j.ajo.2010.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 10/14/2010] [Indexed: 11/22/2022]
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Proust H, Baeteman C, Matonti F, Conrath J, Ridings B, Hoffart L. Femtosecond laser-assisted decagonal penetrating keratoplasty. Am J Ophthalmol 2011; 151:29-34. [PMID: 21047618 DOI: 10.1016/j.ajo.2010.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 07/19/2010] [Accepted: 07/20/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE To assess the use of a new polygonal trephination pattern for penetrating keratoplasty (PK) assisted by femtosecond laser. DESIGN Prospective, nonrandomized clinical study. METHODS Sixteen eyes underwent decagonal PK. Nine had Fuchs dystrophy, 4 had pseudophakic bullous keratopathy, 1 had experienced trauma, 1 had corneal amyloidosis, and 1 had keratoconus. A Femtec (Tecnolas PerfectVision) laser was used to create decagonal penetrating cuts on both donor and recipient corneas. All patients were evaluated for uncorrected visual acuity, best spectacle-corrected visual acuity, pachymetry, topography, and endothelial cell density. Scanning electron microscopy was performed on corneal tissue after surgery. RESULTS All eyes were treated successfully without intraoperative complications. The mean follow-up ± standard deviation was 9.75 ± 3.5 months. Mean postoperative best spectacle-corrected visual acuity was 20/53, and there was a significant improvement in both uncorrected visual acuity (P = .0019) and best spectacle-corrected visual acuity (P = .001). At 6 months, mean ± standard deviation manifest astigmatism was 1.90 ± 1.20 diopters. Mean endothelial cell density was 1502 ± 458 cells/mm². Scanning electron microscopy displayed straight decagonal cut margins and minor remaining tissue bridges. CONCLUSIONS Use of the decagonal trephination profile was effective and safe to perform PK. Short-term visual results and refractive results are encouraging compared with those of conventional PK studies. Longer-term follow-up and comparative studies are necessary to determine precisely advantages the and optimal surgical settings of this technique.
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The Evolution of Contemporary Keratoplasty. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00119-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Penetrating Keratoplasty. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00121-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Farid M, Garg S, Steinert RF. Femtosecond Laser-assisted Penetrating Keratoplasty. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Toytman I, Silbergleit A, Simanovski D, Palanker D. Multifocal laser surgery: cutting enhancement by hydrodynamic interactions between cavitation bubbles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:046313. [PMID: 21230396 DOI: 10.1103/physreve.82.046313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 10/01/2010] [Indexed: 05/30/2023]
Abstract
Transparent biological tissues can be precisely dissected with ultrafast lasers using optical breakdown in the tight focal zone. Typically, tissues are cut by sequential application of pulses, each of which produces a single cavitation bubble. We investigate the hydrodynamic interactions between simultaneous cavitation bubbles originating from multiple laser foci. Simultaneous expansion and collapse of cavitation bubbles can enhance the cutting efficiency, by increasing the resulting deformations in tissue, and the associated rupture zone. An analytical model of the flow induced by the bubbles is presented and experimentally verified. The threshold strain of the material rupture is measured in a model tissue. Using the computational model and the experimental value of the threshold strain one can compute the shape of the rupture zone in tissue resulting from application of multiple bubbles. With the threshold strain of 0.7 two simultaneous bubbles produce a continuous cut when applied at the distance 1.35 times greater than that required in sequential approach. Simultaneous focusing of the laser in multiple spots along the line of intended cut can extend this ratio to 1.7. Counterpropagating jets forming during collapse of two bubbles in materials with low viscosity can further extend the cutting zone-up to approximately a factor of 1.5.
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Affiliation(s)
- I Toytman
- Hansen Experimental Physics Laboratory, Stanford University, 452 Lomita Mall, Stanford, California 94305, USA.
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Abstract
PURPOSE OF REVIEW A look at the recent advances in corneal transplantation surgery using the femtosecond laser technology. RECENT FINDINGS The femtosecond laser uses near-infrared light to create photodisruption, a process that allows corneal tissue to be cut at precise depths and in various patterns. Penetrating keratoplasty as well as disease targeted lamellar corneal surgery have been performed using this technology in order to improve surgical outcomes and wound healing. It is now possible to create customized trephination patterns, including 'zig-zag' and 'top-hat', which demonstrate more rapid visual recovery and decreased amounts of astigmatism as compared with conventional blade trephination penetrating keratoplasty. The benefits of these cuts have been extended into the deep anterior lamellar keratoplasty surgery in order to maintain the benefits of the customized cut, whereas preserving the endothelial layer in ectatic and stromal diseases of the cornea. SUMMARY Femtosecond laser-assisted corneal surgery is improving traditional outcomes in transplantation. Continued studies using this ultrafast laser may continue to yield new and exciting possibilities in the treatment of corneal disease.
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Current world literature. Refractive surgery. Corneal and external disorders. Curr Opin Ophthalmol 2010; 21:322-6. [PMID: 20548165 DOI: 10.1097/icu.0b013e32833bb58c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Jung KI, Choi JA, Na KS, Chung SH, Tchah H, Kim EK, Joo CK. Comparison of Outcomes of Femtosecond Laser-assisted Keratoplasty and Conventional Penetrating Keratoplasty. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2010. [DOI: 10.3341/jkos.2010.51.8.1054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Kyoung In Jung
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
| | - Jin A Choi
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
| | - Kyung Sun Na
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
| | - So Hyang Chung
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
| | - Hungwon Tchah
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Eung Kweon Kim
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
| | - Choun-Ki Joo
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea
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