1
|
Tolba MY, Zaki IMA, Raafat KA, Dib AAA, Eleiwa T, Chase C, Taher IM. Electron microscopic comparison of the donor cut edges using femtosecond laser-assisted keratoplasty versus conventional keratoplasty. Saudi J Ophthalmol 2021; 35:47-51. [PMID: 34667932 PMCID: PMC8486028 DOI: 10.4103/1319-4534.325785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/10/2020] [Accepted: 12/13/2020] [Indexed: 11/22/2022] Open
Abstract
PURPOSE: To describe and compare the histological changes in the cut edges of the remaining donor corneal rim using femtosecond laser-assisted keratoplasty (FAK) versus conventional penetrating keratoplasty (PK) via light and transmission electron microscopic examination. METHODS: This was a prospective observational study of 10 eyes; 5 FAK (top-hat technique) and 5 conventional PK. Main outcomes were histological findings at the cut edge of the donor corneal rim (at 3, 6, 9, and 12 o'clock). RESULTS: Cellular and ultra-cellular changes in the form of stromal edema, disorganized collagen fibers, and nuclear changes were more prominent in the FAK eyes as compared to the conventional PK ones. CONCLUSION: FAK induces more collateral damage in the cut edge of corneal donor graft at cellular and ultra-cellular levels, compared to conventional trephination. Further studies are required to investigate the clinical ramifications of this observation.
Collapse
Affiliation(s)
- Mohamed Y Tolba
- Ophthalmology Department, Eye Specialty Hospital, Medical Military Compound, Koubri Elkouba, Cairo, Egypt
| | - Iman M A Zaki
- Pathology Department, Research Institute of Ophthalmology, Cairo University, Cairo, Egypt
| | - Karim A Raafat
- Ophthalmology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Amr A Al Dib
- Ophthalmology Department, National Institute For LASER Science , Cairo University, Cairo, Egypt
| | - Taher Eleiwa
- Ophthalmology Department, Faculty of Medicine, Benha University, Benha, Egypt
| | - Collin Chase
- Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Ibrahim M Taher
- Ophthalmology Department, National Institute For LASER Science , Cairo University, Cairo, Egypt
| |
Collapse
|
2
|
Price MO, Mehta JS, Jurkunas UV, Price FW. Corneal endothelial dysfunction: Evolving understanding and treatment options. Prog Retin Eye Res 2020; 82:100904. [PMID: 32977001 DOI: 10.1016/j.preteyeres.2020.100904] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/14/2020] [Accepted: 09/19/2020] [Indexed: 12/13/2022]
Abstract
The cornea is exquisitely designed to protect the eye while transmitting and focusing incoming light. Precise control of corneal hydration by the endothelial cell layer that lines the inner surface of the cornea is required for optimal transparency, and endothelial dysfunction or damage can result in corneal edema and visual impairment. Advances in corneal transplantation now allow selective replacement of dysfunctional corneal endothelium, providing rapid visual rehabilitation. A series of technique improvements have minimized complications and various adaptations allow use even in eyes with complicated anatomy. While selective endothelial keratoplasty sets a very high standard for safety and efficacy, a shortage of donor corneas in many parts of the world restricts access, prompting a search for alternatives. Clinical trials are underway to evaluate the potential for self-recovery after removal of dysfunctional central endothelium in patients with healthy peripheral endothelium. Various approaches to using cultured human corneal endothelial cells are also in clinical trials; these aim to multiply cells from a single donor cornea for use in potentially hundreds of patients. Pre-clinical studies are underway with induced pluripotent stem cells, endothelial stem cell regeneration, gene therapy, anti-sense oligonucleotides, and various biologic/pharmacologic approaches designed to treat, prevent, or retard corneal endothelial dysfunction. The availability of more therapeutic options will hopefully expand access around the world while also allowing treatment to be more precisely tailored to each individual patient.
Collapse
Affiliation(s)
- Marianne O Price
- Cornea Research Foundation of America, 9002 N. Meridian St., Suite 212, Indianapolis, IN, USA.
| | - Jodhbir S Mehta
- Singapore National Eye Centre, 11 Third Hospital Ave #08-00, 168751, Singapore
| | - Ula V Jurkunas
- Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, USA
| | - Francis W Price
- Price Vision Group, 9002 N. Meridian St., Suite 100, Indianapolis, IN, USA
| |
Collapse
|
3
|
Han SB, Liu YC, Mohamed-Noriega K, Mehta JS. 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.
Collapse
Affiliation(s)
- Sang Beom Han
- Department of Ophthalmology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, Republic of Korea
| | - Yu-Chi Liu
- Singapore National Eye Centre, Singapore
- Singapore Eye Research Institute, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Karim Mohamed-Noriega
- Department of Ophthalmology, University Hospital, Faculty of Medicine, Autonomous University of Nuevo Leon, Monterrey, Mexico
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore
- Singapore Eye Research Institute, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
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
| | | |
Collapse
|
7
|
Tóth G, Szentmáry N, Langenbucher A, Akhmedova E, El-Husseiny M, Seitz B. Comparison of Excimer Laser Versus Femtosecond Laser Assisted Trephination in Penetrating Keratoplasty: A Retrospective Study. Adv Ther 2019; 36:3471-3482. [PMID: 31650512 DOI: 10.1007/s12325-019-01120-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Indexed: 11/30/2022]
Abstract
INTRODUCTION To compare the impact of non-mechanical excimer-assisted (EXCIMER) and femtosecond laser-assisted (FEMTO) trephination on outcomes after penetrating keratoplasty (PK). METHODS In this retrospective study, 68 eyes from 23 females and 45 males (mean age at time of surgery, 53.3 ± 19.8 years) were included. Inclusion criteria were one surgeon (BS), primary central PK, Fuchs' dystrophy (FUCHS) or keratoconus (KC), no previous intraocular surgery, graft oversize 0.1 mm and 16-bite double running suture. Trephination was performed using a manually guided 193-nm Zeiss Meditec MEL70 excimer laser (EXCIMER group: 18 FUCHS, 17 KC) or 60-kHz IntraLase™ femtosecond laser (FEMTO group: 16 FUCHS, 17 KC). Subjective refractometry (trial glasses) and corneal topography analysis (Pentacam HR; Casia SS-1000 AS-OCT; TMS-5) were performed preoperatively, before removal of the first suture (11.4 ± 1.9 months) and after removal of the second suture (22.6 ± 3.8 months). RESULTS Before suture removal, mean refractive/AS-OCT topographic astigmatism did not differ significantly between EXCIMER and FEMTO. After suture removal, mean refractive/Pentacam/AS-OCT topographic astigmatism was significantly higher in the FEMTO (6.2 ± 2.9 D/7.1 ± 3.2 D/7.4 ± 3.3 D) than in the EXCIMER patients (4.3 ± 3.0 D/4.4 ± 3.1 D/4.0 ± 2.9 D) (p ≤ 0.005). Mean corrected distance visual acuity increased from 0.22 and 0.23 preoperatively to 0.55 and 0.53 before or 0.7 and 0.6 after suture removal in the EXCIMER and FEMTO groups, respectively. Differences between EXCIMER and FEMTO were only pronounced in the KC subgroup. CONCLUSION Non-mechanical EXCIMER trephination seems to have advantages regarding postoperative corneal astigmatism and visual acuity compared with FEMTO trephination, especially in KC. A bigger sample size and longer follow-up are needed to evaluate the long-term impact of EXCIMER and FEMTO trephination on postoperative topographic and visual outcomes.
Collapse
Affiliation(s)
- Gábor Tóth
- Department of Ophthalmology, Saarland University Medical Center, Kirrberger Str. 100, 66424, Homburg/Saar, Germany.
- Department of Ophthalmology, Semmelweis University, Mária utca 39, 1085, Budapest, Hungary.
| | - Nóra Szentmáry
- Department of Ophthalmology, Saarland University Medical Center, Kirrberger Str. 100, 66424, Homburg/Saar, Germany
- Department of Ophthalmology, Semmelweis University, Mária utca 39, 1085, Budapest, Hungary
| | - Achim Langenbucher
- Experimental Ophthalmology, Saarland University, Kirrberger Str. 100, 66424, Homburg/Saar, Germany
| | - Elina Akhmedova
- Department of Ophthalmology, Saarland University Medical Center, Kirrberger Str. 100, 66424, Homburg/Saar, Germany
| | - Moatasem El-Husseiny
- Department of Ophthalmology, Saarland University Medical Center, Kirrberger Str. 100, 66424, Homburg/Saar, Germany
| | - Berthold Seitz
- Department of Ophthalmology, Saarland University Medical Center, Kirrberger Str. 100, 66424, Homburg/Saar, Germany
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
|
10
|
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.
Collapse
|
11
|
Uy HS, Chan PS, Gil-Cazorla R, Shah S. Comparison of surgical parameters using different lens fragmentation patterns in eyes undergoing laser-assisted cataract surgery. Int Ophthalmol 2019; 39:2459-2465. [PMID: 30830545 DOI: 10.1007/s10792-019-01087-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 02/23/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To compare surgical parameters among eyes undergoing laser-assisted cataract surgery (LACS) using different lens fragmentation patterns (LFP). METHODS Prospective, randomized, unmasked clinical trial. One-hundred eyes underwent LACS and were randomly assigned to 1 of 3 LFP treatment groups: (1) laser capsulotomy only; no lens fragmentation (NLF) (n = 34); (2) three-plane chop (TPC) (n = 33); and, (3) pie-cut pattern (PCP) fragmentation (n = 33). Prechop phacoemulsification (PHACO) was performed on all eyes using the same femtosecond (FS) laser and active-fluidics PHACO machine. MAIN OUTCOME MEASURES FS laser dock time (s), PHACO time (s), PHACO power (%), cumulative dissipated energy (CDE) (%-s), irrigating fluid volume, and operative time. RESULTS The 3 treatment groups were comparable in terms of patient age (P = 0.164) and nuclear density (P = 0.669). FS dock time was higher in the PCP group (184.18 ± 25.86) compared to the TPC (145.09 ± 14.15) group (P < 0.001). PHACO time was significantly shorter in the PCP (23.19 ± 17.20 s) compared to TPC (35.27 ± 17.70) and NLF (46.15 ± 23.72) groups (P < 0.001). PHACO power was lower in the PCP (11.81 ± 3.71) compared to the NLF (14.41 ± 1.88) and TPC (14.04 ± 2.46) groups (P < 0.001). CDE was lower in the PCP (2.85 ± 2.32) compared to NLF (6.55 ± 3.32) and TPC (6.55 ± 5.45) groups (P < 0.001). Fluid volumes and operative times were similar. CONCLUSION LFP can influence PHACO surgical parameters. Extensive fragmentation patterns such as PCP appear to lower PHACO time, power, and CDE and may potentially reduce the risk of PHACO related complications.
Collapse
Affiliation(s)
- Harvey S Uy
- Peregrine Eye and Laser Institute, 50 Jupiter Street, 1209, Makati City, Philippines. .,Department of Ophthalmology and Visual Sciences, University of the Philippines, Manila, Philippines.
| | - Pik Sha Chan
- Peregrine Eye and Laser Institute, 50 Jupiter Street, 1209, Makati City, Philippines
| | | | - Sunil Shah
- Birmingham and Midland Eye Centre, Birmingham, UK
| |
Collapse
|
12
|
Endothelial cell density and corneal graft thickness following excimer laser vs. femtosecond laser-assisted penetrating keratoplasty—a prospective randomized study. Graefes Arch Clin Exp Ophthalmol 2019; 257:975-981. [DOI: 10.1007/s00417-019-04263-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 01/31/2019] [Accepted: 02/09/2019] [Indexed: 10/27/2022] Open
|
13
|
Canovetti A, Rossi F, Rossi M, Menabuoni L, Malandrini A, Pini R, Ferrara P. Anvil-profiled penetrating keratoplasty: load resistance evaluation. Biomech Model Mechanobiol 2018; 18:319-325. [PMID: 30382505 DOI: 10.1007/s10237-018-1083-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/15/2018] [Indexed: 10/28/2022]
Abstract
The aim of this study was to qualitatively evaluate the biomechanical load resistance of different surgical wound configurations (mushroom, zig-zag, anvil and conventional trephination) in penetrating keratoplasty (PK) by designing a 2D and a 3D finite-element biomechanical model of the cornea. A mathematical model of the human cornea was developed, and different geometric configurations for PK were designed. The internal pressure was raised until the wound misaligned; wound prolapse then occurred. Better wound resistance was found in all the laser trephined profiles tested in comparison with the conventional straight one. The anvil profile was more resistant to the increasing internal pressure than was the mushroom or the zig-zag pattern. Thanks to its greater mechanical load resistance, the anvil profile made possible the apposition of a restricted number of sutures and early suture removal. These advantages can contribute to a faster visual recovery in patients undergoing penetrating keratoplasty.
Collapse
Affiliation(s)
- Annalisa Canovetti
- U.O. Oculistica Asl 4, Nuovo Ospedale S. Stefano, Via Suor Niccolina Infermiera, 59100, Prato, Italy
| | - Francesca Rossi
- Istituto di Fisica Applicata, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy.
| | - Michele Rossi
- Istituto di Fisica Applicata, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy
| | - Luca Menabuoni
- U.O. Oculistica Asl 4, Nuovo Ospedale S. Stefano, Via Suor Niccolina Infermiera, 59100, Prato, Italy
| | - Alex Malandrini
- U.O. Oculistica Asl 4, Nuovo Ospedale S. Stefano, Via Suor Niccolina Infermiera, 59100, Prato, Italy
| | - Roberto Pini
- Istituto di Fisica Applicata, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy
| | - Paolo Ferrara
- Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Via G. Moruzzi 1, 56124, Pisa, Italy
| |
Collapse
|
14
|
Resch MD, Zemova E, Marsovszky L, Szentmáry N, Bauer F, Daas L, Pattmöller M, El-Husseiny M, Németh J, Nagy ZZ, Seitz B. In Vivo Confocal Microscopic Imaging of the Cornea After Femtosecond and Excimer Laser-assisted Penetrating Keratoplasty. J Refract Surg 2016; 31:620-6. [PMID: 26352568 DOI: 10.3928/1081597x-20150820-08] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/16/2015] [Indexed: 11/20/2022]
Abstract
PURPOSE To examine the microstructure of the cornea after excimer and femtosecond laser-assisted penetrating keratoplasty (ELAK and FLAK) in eyes with Fuchs' dystrophy and keratoconus. METHODS Fifty-seven patients were divided into four groups according to corneal disease and surgical technique: Fuchs' dystrophy and ELAK (n = 9; mean age: 70.4 ± 10.6 years); Fuchs' dystrophy and FLAK (n = 13; mean age: 64.3 ± 11.2 years); keratoconus and ELAK (n = 9; mean age: 47.4 ± 13.9 years); and keratoconus and FLAK (n = 9; mean age: 43.5 ± 13.8 years). The control group comprised individuals without ocular disease (n = 17; mean age: 39.9 ± 17.3 years). In vivo investigation of the corneal graft and graft-host junction zone was performed with confocal corneal microscopy. RESULTS All corneal grafts were transparent and no rejection reaction could be observed during the follow-up period. Confocal microscopy revealed no difference in basal epithelial cell density compared to controls. Anterior keratocyte density was lower than in the control group (818 ± 131 cells/mm(2)) in all four treatment groups (596 ± 174, 586 ± 113, 529 ± 75, 552 ± 91 cells/mm(2)). Langerhans cells could barely be seen; there was no difference in the cutting edge configuration and wound integrity. CONCLUSIONS In vivo confocal microscopy provided evidence that good alignment of graft-host junction could be created with both techniques. The excimer laser was not inferior to the femtosecond laser in performing corneal cuts. The low density of Langerhans cells revealed well-controlled cellular immunological response and sustained corneal integrity in both laser groups.
Collapse
|
15
|
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]
|
16
|
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]
|
17
|
A Comparison of Different Operating Systems for Femtosecond Lasers in Cataract Surgery. J Ophthalmol 2015; 2015:616478. [PMID: 26483973 PMCID: PMC4592914 DOI: 10.1155/2015/616478] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/06/2015] [Accepted: 06/23/2015] [Indexed: 02/06/2023] Open
Abstract
The introduction of femtosecond lasers is potentially a major shift in the way we approach cataract surgery. The development of increasingly sophisticated intraocular lenses (IOLs), coupled with heightened patient expectation of high quality postsurgical visual outcomes, has generated the need for a more precise, highly reproducible and standardized method to carry out cataract operations. As femtosecond laser-assisted cataract surgery (FLACS) becomes more commonplace in surgical centers, further evaluation of the potential risks and benefits needs to be established, particularly in the medium/long term effects. Healthcare administrators will also have to weigh and balance out the financial costs of these lasers relative to the advantages they put forth. In this review, we provide an operational overview of three of five femtosecond laser platforms that are currently commercially available: the Catalys (USA), the Victus (USA), and the LDV Z8 (Switzerland).
Collapse
|
18
|
Aristeidou A, Taniguchi EV, Tsatsos M, Muller R, McAlinden C, Pineda R, Paschalis EI. The evolution of corneal and refractive surgery with the femtosecond laser. EYE AND VISION 2015; 2:12. [PMID: 26605365 PMCID: PMC4655461 DOI: 10.1186/s40662-015-0022-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 06/20/2015] [Indexed: 01/12/2023]
Abstract
The use of femtosecond lasers has created an evolution in modern corneal and refractive surgery. With accuracy, safety, and repeatability, eye surgeons can utilize the femtosecond laser in almost all anterior refractive procedures; laser in situ keratomileusis (LASIK), small incision lenticule extraction (SMILE), penetrating keratoplasty (PKP), insertion of intracorneal ring segments, anterior and posterior lamellar keratoplasty (Deep anterior lamellar keratoplasty (DALK) and Descemet's stripping endothelial keratoplasty (DSEK)), insertion of corneal inlays and cataract surgery. As the technology matures, it will push surgical limits and open new avenues for ophthalmic intervention in areas not yet explored. As we witness the transition from femto-LASIK to femto-cataract surgery it becomes obvious that this innovation is here to stay. This article presents some of the most relevant advances of femtosecond lasers to modern corneal and refractive surgery.
Collapse
Affiliation(s)
| | - Elise V Taniguchi
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA USA ; Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Boston Keratoprosthesis Laboratory, Harvard Medical School, Boston, 02114 MA USA
| | | | - Rodrigo Muller
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA USA
| | - Colm McAlinden
- Flinders University, Adelaide, South Australia Australia ; Wenzhou Medical University, Wenzhou, Zhejiang China
| | - Roberto Pineda
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA USA
| | - Eleftherios I Paschalis
- Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA USA ; Massachusetts Eye and Ear Infirmary/Schepens Eye Research Institute, Boston Keratoprosthesis Laboratory, Harvard Medical School, Boston, 02114 MA USA
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
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.
Collapse
Affiliation(s)
- Yathish Shivanna
- Narayana Nethralaya, Department of Cornea and Refractive Services, Bangalore, Karnataka, India
| | | | | | | |
Collapse
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Kimakura M, Sakai O, Nakagawa S, Yoshida J, Shirakawa R, Toyono T, Yokoo S, Amano S. Stromal bed quality and endothelial damage after femtosecond laser cuts into the deep corneal stroma. Br J Ophthalmol 2013; 97:1404-9. [PMID: 24008824 DOI: 10.1136/bjophthalmol-2013-303328] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIM To evaluate the stromal bed quality and endothelial damage after femtosecond laser (FSL) cuts into the deep corneal stroma. METHODS Using a 150-kHz FSL, a lamellar cut was aimed at a depth of 100, 300, or 500 μm in porcine corneas. Stromal bed smoothness was graded from light microscopy and scanning electron microscopy images. Rabbit corneas were cut at remaining thicknesses of 70, 100 and 150 μm using the FSL. The effects of peeling off the corneal flap and the distance between laser spots (2 or 4 μm) were examined. RESULTS The ratio of damaged cells in the group with a remaining depth of 70 μm was significantly larger than that in the groups with a remaining depth of 150 μm. The ratio of damaged cells in the group with a 4-μm spot separation and the flap peeled off was significantly larger than that in the group with a 4-μm spot separation and the flap not peeled off. CONCLUSIONS Corneal endothelial damage is likely to increase when the remaining depth is less than 70 μm, and peeling off the flap damages corneal endothelial cells when the remaining depth is less than 100 μm.
Collapse
Affiliation(s)
- Mikiko Kimakura
- Department of Ophthalmology, University of Tokyo School of Medicine, , Tokyo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
23
|
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.
Collapse
|
24
|
|
25
|
|
26
|
|
27
|
Improved wound stability of top-hat profiled femtosecond laser-assisted penetrating keratoplasty in vitro. Cornea 2012; 31:963-6. [PMID: 22406945 DOI: 10.1097/ico.0b013e3182400048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The femtosecond laser is a new option for cutting corneal tissue at high precision. The "top-hat" profile has an overlapping graft-host interface at the edge because of a larger inner trephination diameter. This may enhance graft fixation, thus improving the outcome and accelerating rehabilitation after penetrating keratoplasty. METHODS Femtosecond laser top-hat keratoplasties with overlaps of 0 and 3 mm between inner and outer trephination diameters were performed in vitro. After trephination, the excised corneal buttons were readapted by different suturing profiles. Pressure in the artificial anterior chamber was then raised until we observed wound leakage and ultimately wound prolapse. RESULTS Better wound stability was found in conjunction with all profiled trephinations. When using 4 interrupted sutures, wound leakage occurred at a median of 13.0 cm H2O (mean, 12.3 cm H2O) and "zero overlap," at 19.0 cm H2O (mean, 20.8 cm H2O) and 1-mm overlap, at 32.0 cm H2O (mean, 32.8 cm H2O) and 2-mm overlap, and at 48.5 cm H2O (mean, 49.4 cm H2O) and 3-mm overlap. Comparing zero overlap with the mean values of 1- to 3-mm overlaps, wound leakage happened at 13.0 (mean, 12.3) versus 32.0 (mean, 34.3) cm H2O with 4 interrupted sutures, at 57.5 (mean, 58.3) versus 61.0 (mean, 70.8) cm H2O with 8 interrupted sutures, at 31.5 (mean, 32.0) versus >97.0 (mean, 75.5) cm H2O with 1 running and 4 interrupted sutures, and at 34.0 (mean, 32.3) versus 80.0 (mean, 69.9) cm H2O with 1 running suture. The analysis of variance revealed a statistically significant increase in wound stability for all overlaps independently from the size of the overlap. CONCLUSIONS Femtosecond laser-assisted profiles with even small overlaps for penetrating keratoplasty may make fewer sutures and earlier suture removal possible because of better wound stability, contributing to earlier visual recovery and helping to prevent wound rupture after trauma. However, further study is required to identify the optimum profile including the various technical parameters.
Collapse
|
28
|
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.
Collapse
|
29
|
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.
Collapse
Affiliation(s)
- Florian Birnbaum
- Eye Hospital, Klinikum Bremen-Mitte gGmbH, St.-Jürgenstr. 1, 28177 Bremen, Germany.
| | | | | | | | | |
Collapse
|
30
|
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.
Collapse
|
31
|
Sun H, Hosszufalusi N, Mikula ER, Juhasz T. Simulation of the temperature increase in human cadaver retina during direct illumination by 150-kHz femtosecond laser pulses. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:108001. [PMID: 22029369 PMCID: PMC3206930 DOI: 10.1117/1.3631788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/02/2011] [Accepted: 08/08/2011] [Indexed: 05/31/2023]
Abstract
We have developed a two-dimensional computer model to predict the temperature increase of the retina during femtosecond corneal laser flap cutting. Simulating a typical clinical setting for 150-kHz iFS advanced femtosecond laser (0.8- to 1-μJ laser pulse energy and 15-s procedure time at a laser wavelength of 1053 nm), the temperature increase is 0.2°C. Calculated temperature profiles show good agreement with data obtained from ex vivo experiments using human cadaver retina. Simulation results obtained for different commercial femtosecond lasers indicate that during the laser in situ keratomileusis procedure the temperature increase of the retina is insufficient to induce damage.
Collapse
Affiliation(s)
- Hui Sun
- University of California, Irvine, Department of Ophthalmology, Irvine, California 92697, USA
| | | | | | | |
Collapse
|
32
|
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]
|
33
|
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.
Collapse
|
34
|
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]
|
35
|
Dick HB, Willert A, Elling M. Real-time measurement of intraocular pressure during femtosecond laser enabled keratoplasty. J Refract Surg 2011; 27:399-400. [PMID: 21667894 DOI: 10.3928/1081597x-20110217-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
36
|
“Tuck In” Lamellar Keratoplasty for Tectonic Management of Postkeratoplasty Corneal Ectasia With Peripheral Corneal Involvement. Cornea 2011; 30:171-4. [DOI: 10.1097/ico.0b013e3181ead943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
37
|
Sixty-Kilohertz Femtosecond Laser–Assisted Endothelial Keratoplasty: Clinical Results and Stromal Bed Quality Evaluation. Cornea 2011; 30:189-93. [DOI: 10.1097/ico.0b013e3181ead924] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
38
|
Temperature increase in porcine cadaver iris during direct illumination by femtosecond laser pulses. J Cataract Refract Surg 2011; 37:386-91. [PMID: 21241925 DOI: 10.1016/j.jcrs.2010.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 08/12/2010] [Accepted: 09/10/2010] [Indexed: 11/22/2022]
Abstract
PURPOSE To measure the temperature rise in porcine cadaver iris during direct illumination by the femtosecond laser as a model for laser exposure of the iris during femtosecond laser corneal surgery. SETTING Department of Ophthalmology, University of California-Irvine, Irvine, California, USA. DESIGN Experimental study. METHODS The temperature increase induced by a 60 kHz commercial femtosecond laser in porcine cadaver iris was measured in situ using an infrared thermal imaging camera at pulse energy levels ranging from 1 to 2 μJ (corresponding approximately to surgical energies of 2 to 4 μJ per laser pulse). RESULTS Temperature increases up to 2.3 °C (corresponding to 2 μJ and 24-second illumination) were observed in the porcine cadaver iris with little variation in temperature profiles between specimens for the same laser energy illumination. CONCLUSIONS The 60 kHz commercial femtosecond laser operating with pulse energies at approximately the lower limit of the range evaluated in this study would be expected to result in a 1.2 °C temperature increase and therefore does not present a safety hazard to the iris.
Collapse
|
39
|
Van Meter W, Katz DG. Keratoplasty Suturing Techniques. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00123-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
40
|
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.
Collapse
|
41
|
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]
|
42
|
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]
|
43
|
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.
Collapse
|
44
|
Nuzzo V, Savoldelli M, Legeais JM, Plamann K. Self-focusing and spherical aberrations in corneal tissue during photodisruption by femtosecond laser. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:038003. [PMID: 20615049 DOI: 10.1117/1.3455507] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The use of ultrashort pulse lasers is current in refractive surgery and has recently been extended to corneal grafting (keratoplasty). When performing keratoplasty, however, permanent degradation of the optical properties of the patient's cornea compromises the penetration depth of the laser and the quality of the incisions, therefore causing unwanted secondary effects. Additionally, corneal grafting needs considerably higher penetration depths than refractive surgery. Little data are available about the interaction processes of the femtosecond pulses in the volume of pathological corneas-i.e., in the presence of spherical aberrations and optical scattering. We investigate the influence of the focusing numerical aperture on the laser-tissue interaction. We point out that at low numerical apertures (NAs), tissue damage is produced below and above the focal region. We attribute this phenomenon to nonlinear self-focusing effects. On the other hand, at high NAs, spherical aberrations become significant when focusing at high depths for posterior surgeries, which also limit the cutting efficiency. As high NAs are advisable for reducing unwanted nonlinear effects and ensure accurate cutting, particular attention should be paid to aberration management when developing clinical femtosecond lasers.
Collapse
Affiliation(s)
- Valeria Nuzzo
- Laboratoire d'Optique Appliquee, ENSTA-Ecole Polytechnique-CNRS UMR 7639, Chemin de la Huniere, 91761 Palaiseau cedex, France.
| | | | | | | |
Collapse
|
45
|
|
46
|
Abstract
Newer forms of lamellar keratoplasty techniques have emerged in the last decade or so revolving around the concept of targeted replacement of diseased corneal layers. These include anterior lamellar keratoplasty (ALK) techniques that aim to selectively replace diseased corneal stroma and, endothelial keratoplasty techniques aiming to replaced damaged endothelium in endothelial disorders. ALK surgery has a distinct advantage over penetrating keratoplasty (PK) in that it minimizes unnecessary replacement of the unaffected healthy endothelial layer thereby almost eliminating the risk of endothelial rejection, a major cause of graft failure in PK. Overall it provides increased life expectancy to the graft and with advancements in the surgical technique and instrumentation for ALK, the visual outcomes are now comparable if not better to standard PK. There are several forms of ALK procedures that have evolved to cater to a wide range of stromal disorders. This article reviews the various emerging techniques of anterior lamellar surgery, its indications and visual outcomes, to emphasize the shift from PK to ALK for stromal disorders with a healthy endothelium.
Collapse
Affiliation(s)
- Donald T H Tan
- Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751.
| | | |
Collapse
|
47
|
Abstract
A number of corneal disorders sooner or later call for a decision as to whether corneal grafting is necessary. The problems of the current gold standard treatment, conventional penetrating keratoplasty (PKP), have yet to be fully solved, namely accelerated postoperative endothelial cell loss, endothelial immune reactions and the induction of astigmatism, which depends among other things on the trephination technique used. The use of a hand trephine may lead to different cutting angles between donor and recipient, resulting in increased postoperative astigmatism. This technique is therefore now only used for certain indications. One major advantage of mechanically guided trephine systems, which are now considered standard, is the possibility of trephining the donor disc from the epithelial side to avoid donor oversizing, therefore reducing postoperative astigmatism. Even less astigmatism is induced in keratoconus patients using an Excimer laser for trephination, as this technique does not lead to corneal deformation during trephination. Furthermore, this non-contact method can also be used to trephine unstable corneas. Femtosecond lasers allow the creation not only of straight but also profiled trephination edges, leading to more stable wound healing and hence earlier suture removal.
Collapse
|
48
|
Nuzzo V, Aptel F, Savoldelli M, Plamann K, Peyrot D, Deloison F, Donate D, Legeais JM. Histologic and Ultrastructural Characterization of Corneal Femtosecond Laser Trephination. Cornea 2009; 28:908-13. [DOI: 10.1097/ico.0b013e318197ebeb] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
49
|
Top-hat Shaped Corneal Trephination for Penetrating Keratoplasty Using the Femtosecond Laser: A Histomorphological Study. Cornea 2009; 28:795-800. [PMID: 19574905 DOI: 10.1097/ico.0b013e31819839c6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
50
|
Price FW, Price MO, Grandin JC, Kwon R. Deep anterior lamellar keratoplasty with femtosecond-laser zigzag incisions. J Cataract Refract Surg 2009; 35:804-8. [PMID: 19393877 DOI: 10.1016/j.jcrs.2009.01.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 12/21/2008] [Accepted: 01/01/2009] [Indexed: 01/18/2023]
Abstract
We describe a technique that uses IntraLase-created zigzag incisions for deep anterior lamellar keratoplasty. In this technique, the laser creates a precise incision that extends to within 70 microm of the recipient Descemet membrane. The deep incision minimizes air escape into the peripheral cornea during big-bubble formation. In cases that require hand dissection, the deep incision provides a reference for gauging the dissection depth. The angled incision edge facilitates final stromal excision with scissors. Compared with standard vertical incisions, the zigzag incision provides an interlocking wound configuration and facilitates matching the donor and recipient anterior surfaces.
Collapse
Affiliation(s)
- Francis W Price
- Price Vision Group, Cornea Research Foundation of America, Indianapolis, Indiana 46260, USA
| | | | | | | |
Collapse
|