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Wagner FM, Sekundo W. Iatrogenic Keratectasia after Refractive Surgery - Causes, Prophylaxis, Therapy. Klin Monbl Augenheilkd 2023; 240:783-794. [PMID: 37348513 DOI: 10.1055/a-2073-8478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
Iatrogenic keratectasia is induced thinning and protrusion of the cornea after laser refractive surgery. Known risk factors include an excessively thin postoperative residual stromal bed, a thicker flap, or preoperatively undetected evidence of preexisting subclinical keratoconus. The rate of post-refractive ectasia in eyes without identifiable preoperative risk factors is 20 per 100 000 eyes for photorefractive keratectomy, 90 per 100 000 eyes for laser in situ keratomileusis, and 11 per 100 000 eyes for small incision lenticule extraction. Traditional screening tools for preoperative risk include the ectasia risk score system and percentage of tissue alteration. More recent methods include corneal elastography and epithelial mapping, in addition to Artificial Intelligence methods for data analysis. Therapy includes contact lenses, cross-linking, implantation of intracorneal ring segments, penetrating or lamellar keratoplasty, and, in early studies, implantation of corneal lenticules.
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Affiliation(s)
- Felix Mathias Wagner
- Universitätsaugenklinik Mainz, Mainz, Deutschland
- Universitätsaugenklinik Marburg, Marburg, Deutschland
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Hu X, Wei R, Liu C, Wang Y, Yang D, Sun L, Xia F, Liu S, Li M, Zhou X. Recent advances in small incision lenticule extraction (SMILE)-derived refractive lenticule preservation and clinical reuse. ENGINEERED REGENERATION 2023. [DOI: 10.1016/j.engreg.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Long-Term Clinical Outcomes of Small-Incision Femtosecond Laser-Assisted Intracorneal Concave Lenticule Implantation in Patients with Keratoconus. J Ophthalmol 2022; 2022:9774448. [PMID: 35340275 PMCID: PMC8942691 DOI: 10.1155/2022/9774448] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/25/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose The purpose of this study was to evaluate the long-term prognosis of small-incision femtosecond laser-assisted intracorneal concave lenticule implantation (SFII) in correction of human keratoconus. Methods This was a prospective study for 11 patients who received SFII after being diagnosed as progressive keratoconus based on the Amsler–Krumeich classification system. Clinical assessment was performed for all the patients prior to and postsurgically at different time points for 5 years. These included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), biomechanically corrected intraocular pressure (bIOP), corneal topography, anterior segment optical coherence tomography (AS-OCT), confocal microscopy, and biomechanical assessment with Corvis ST. Results Comparison of preoperative and 60-month postoperative UDVA and CDVA (P60months=0.081 and 0.001, respectively), all eyes showed an improvement in CDVA. Corneal topography showed no significant changes in corneal anterior K1, K2, posterior K1, K2, posterior elevation, or corneal densitometry compared with preoperative levels (P > 0.05). Corvis ST showed that central corneal thickness (CCT) and stiffness at applanation 1 (SP-A1) were significantly greater 1 week postsurgically when compared to the baseline (P < 0.05) and remained stable thereafter. The lenticule under the AS-OCT remained transparent throughout the entire postsurgical period. Under confocal microscopy, corneal edema and an increase in cell activation and reflectivity were observed at the lenticule-stromal interface within 1 week postoperatively. These reactions gradually subsided with time within 6 months. Conclusion SFII is an effective procedure to prevent the progression of keratoconus due to its minimal invasiveness and capability of maintaining a steady biometry of the cornea.
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Preservation of corneal stromal lenticule: review. Cell Tissue Bank 2022; 23:627-639. [DOI: 10.1007/s10561-021-09990-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 12/22/2021] [Indexed: 11/02/2022]
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Riau AK, Boey KPY, Binte M Yusoff NZ, Goh TW, Yam GHF, Tang KF, Phua CSH, Chen HJ, Chiew YF, Liu YC, Mehta JS. Experiment-Based Validation of Corneal Lenticule Banking in a Health Authority-Licensed Facility. Tissue Eng Part A 2021; 28:69-83. [PMID: 34128385 DOI: 10.1089/ten.tea.2021.0042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
With the expected rise in patients undergoing refractive lenticule extraction worldwide, the number of discarded corneal stromal lenticules will increase. Therefore, establishing a lenticule bank to collect, catalog, process, cryopreserve, and distribute the lenticules (for future therapeutic needs) could be advantageous. In this study, we validated the safety of lenticule banking that involved the collection of human lenticules from our eye clinic, transportation of the lenticules to a Singapore Ministry of Health-licensed lenticule bank, processing, and cryopreservation of the lenticules, which, after 3 months or, a longer term, 12 months, were retrieved and transported to our laboratory for implantation in rabbit corneas. The lenticule collection was approved by the SingHealth Centralised Institutional Review Board (CIRB). Both short-term and long-term cryopreserved lenticules, although not as transparent as fresh lenticules due to an altered collagen fibrillar packing, did not show any sign of rejection and cytotoxicity, and did not induce haze or neovascularization for 16 weeks even when antibiotic and steroidal administration were withdrawn after 8 weeks. The lenticular transparency progressively improved and was mostly clear after 4 weeks, the same period when we observed the stabilization of corneal hydration. We showed that the equalization of the collagen fibrillar packing of the lenticules with that of the host corneal stroma contributed to the lenticular haze clearance. Most importantly, no active wound healing and inflammatory reactions were seen after 16 weeks. Our study suggests that long-term lenticule banking is a feasible approach for the storage of stromal lenticules after refractive surgery.
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Affiliation(s)
- Andri K Riau
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Kenny P Y Boey
- Group Laboratory Operations, Cordlife Group Limited, Singapore, Singapore
| | | | - Tze-Wei Goh
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore
| | - Gary H F Yam
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kin F Tang
- Group Laboratory Operations, Cordlife Group Limited, Singapore, Singapore.,Singapore Laboratory, Cordlife Group Limited, Singapore, Singapore
| | | | - Hui-Jun Chen
- Singapore Laboratory, Cordlife Group Limited, Singapore, Singapore
| | - Yoke F Chiew
- Singapore Laboratory, Cordlife Group Limited, Singapore, Singapore
| | - Yu-Chi Liu
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,Corneal and External Eye Disease Department, Singapore National Eye Centre, Singapore, Singapore
| | - Jodhbir S Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore.,Corneal and External Eye Disease Department, Singapore National Eye Centre, Singapore, Singapore
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Fasolo A, Galzignato A, Pedrotti E, Chierego C, Cozzini T, Bonacci E, Marchini G. Femtosecond laser-assisted implantation of corneal stroma lenticule for keratoconus. Int Ophthalmol 2021; 41:1949-1957. [PMID: 33625651 PMCID: PMC8087609 DOI: 10.1007/s10792-021-01739-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 02/06/2021] [Indexed: 11/28/2022]
Abstract
Purpose To review recent progress, challenges, and future perspectives of stromal keratophakia for the treatment of advanced keratoconus. Methods We systematically reviewed the literature in the PubMed database, last update June 30, 2020. No language restriction was applied. The authors checked the reference lists of the retrieved articles to identify any additional study of interest.
Results Several techniques have been proposed for the treatment of keratoconus in order to avoid or delay keratoplasty. This was primarily due to the lack of accessibility to donor corneas in many countries. The ease and predictability of the more advanced femtosecond lasers used to correct ametropias by stromal lenticule extraction lead to hypothesize that generated refractive lenticules could be implanted into corneal stromal layers to restore volume and alter the refractive properties of the cornea in patients with corneal ectasias. At the same time, new techniques for preservation, customization, and cellular therapy of the corneal stromal have been developed, directing to the valorization of otherwise discarded byproducts such as donor corneas unsuitable for either lamellar of penetrating keratoplasty. Conclusions Femtosecond laser-assisted stromal keratophakia could be a suitable therapeutic option for the treatment of corneal ectasias, especially in patients with advanced keratoconus, providing biomechanical support recovering the pachimetry to nearly normal value at the same time. The accuracy and predictability of the refractive outcome are yet a critical issue and the patient eligible for the procedure still has to be characterized.
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Affiliation(s)
- Adriano Fasolo
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy.,The Veneto Eye Bank Foundation, Venezia, Italy
| | - Alice Galzignato
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy
| | - Emilio Pedrotti
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy.
| | - Chiara Chierego
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy
| | - Tiziano Cozzini
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy
| | - Erika Bonacci
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy
| | - Giorgio Marchini
- Department of Neurosciences, Biomedicine and Movement Sciences, Eye Clinic, U.O.C. di Oculistica-Policlinico G.B. Rossi, University of Verona, P.le L.A. Scuro 10, 37134, Verona, Italy
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Riau AK, Liu YC, Yam GH, Mehta JS. Stromal keratophakia: Corneal inlay implantation. Prog Retin Eye Res 2020; 75:100780. [DOI: 10.1016/j.preteyeres.2019.100780] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/28/2019] [Accepted: 09/02/2019] [Indexed: 12/31/2022]
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Bandeira F, Yam GHF, Liu YC, Devarajan K, Mehta JS. Three-Dimensional Neurite Characterization of Small Incision Lenticule Extraction Derived Lenticules. Invest Ophthalmol Vis Sci 2020; 60:4408-4415. [PMID: 31639827 DOI: 10.1167/iovs.19-27566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We study the density and excitatory response of neurites, and Schwann cells (SCs) in fresh and cryopreserved stromal lenticules derived from small incision lenticule extraction (SMILE). Methods Human stromal lenticules (n = 23) were immunostained for β III-tubulin and imaged using spinning disk confocal laser microscopy, followed by three-dimensional reconstruction, to reveal neurite distribution. The lenticule neurite density (LND) was assessed using a validated neurite tracing and length measurement method with NeuronJ. LND was compared among groups of different lenticule thickness (71-165 μm) obtained from -3 to >-6 diopters (D) corrections. SCs were identified by marker expression and the laser effect on SC-neurite interaction was examined under transmission electron microscopy (TEM). Fresh porcine SMILE-lenticules (n = 18) were used for LND comparison among storage conditions and functional excitatory calcium response assay. Results Using a validated neurite length measurement method, we found an inverse correlation of LND with lenticule thickness. Higher LND was found in thinner lenticules obtained from lower power of correction (r = -0.8925, P < 0.0001), whereas total lenticule neurite lengths did not alter significantly with regards to lenticule thickness. SCs were identified by GAP43 and p75NTR expression and were closely associated with lenticule neurites under TEM. In porcine lenticules, LND and excitatory calcium response were reduced after cold and cryogenic storage, when compared to fresh lenticules. Conclusions The stromal neurites showed variations in density related to SMILE lenticule thickness and cryopreservation. With the presence of SC support and excitatory response, these neurite residues could retain minimal functionality that might serve as a potential advantage in the event of lenticule implantation.
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Affiliation(s)
- Francisco Bandeira
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Federal University of São Paulo, Sao Paulo, Brazil.,São Gonçalo Eye Hospital, Rio de Janeiro, Brazil
| | - Gary Hin-Fai Yam
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Eye-Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore.,Experimental Microscopy Platform, Singapore Eye Research Institute, Singapore
| | - Yu-Chi Liu
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Eye-Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore.,Singapore National Eye Centre, Singapore
| | - Kavya Devarajan
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore
| | - Jodhbir S Mehta
- Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore.,Eye-Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore.,Singapore National Eye Centre, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,School of Material Science and Engineering, Nanyang Technological University, Singapore
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Small-Incision Femtosecond Laser-Assisted Intracorneal Concave Lenticule Implantation in Patients With Keratoconus. Cornea 2019; 38:446-453. [PMID: 30840609 PMCID: PMC6407908 DOI: 10.1097/ico.0000000000001877] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Supplemental Digital Content is Available in the Text. Purpose: To evaluate the feasibility and efficacy of small-incision femtosecond laser–assisted intracorneal concave lenticule implantation (SFII) and penetrating keratoplasty (PKP) in patients with progressive keratoconus. Methods: All the patients were clinically diagnosed with progressive keratoconus. Twenty patients underwent PKP (PKP group), and 11 patients underwent SFII (SFII group). Visual acuity, intraocular pressure, corneal topography, corneal visualization Scheimpflug technology, anterior segment optical coherence tomography, and in vivo confocal microscopy were analyzed. Results: Vision improved at 3 months postoperatively in the SFII group. In the PKP group, corrected distance visual acuity improved 1 week after surgery. Corneal topography showed a statistically significant decrease in the anterior K1 and K2. Corneal visualization Scheimpflug technology showed that changes in the biomechanical parameters of the SFII group were also statistically different from those of the PKP group. All the grafts from both groups were clearly visible by anterior segment optical coherence tomography observation. The central corneal thickness of both groups was stable during the 24-month study period. In vivo confocal microscopy showed a few dendritic cells in the subepithelial region in the SFII group. At 3 months after surgery, many dendritic cells and inflammatory cells were observed in the basal epithelium and stroma in the PKP group. Conclusions: Both SFII and PKP surgical procedures resulted in a stable corneal volume and improved visual acuity in this long-term study. SFII was less invasive and more efficient compared with PKP.
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Carvalho C, Gaspar A, Knight A, Vicente L. Ethical and Scientific Pitfalls Concerning Laboratory Research with Non-Human Primates, and Possible Solutions. Animals (Basel) 2018; 9:E12. [PMID: 30597951 PMCID: PMC6356609 DOI: 10.3390/ani9010012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/18/2018] [Accepted: 12/24/2018] [Indexed: 12/13/2022] Open
Abstract
Basic and applied laboratory research, whenever intrusive or invasive, presents substantial ethical challenges for ethical committees, be it with human beings or with non-human animals. In this paper we discuss the use of non-human primates (NHPs), mostly as animal models, in laboratory based research. We examine the two ethical frameworks that support current legislation and guidelines: deontology and utilitarianism. While human based research is regulated under deontological principles, guidelines for laboratory animal research rely on utilitarianism. We argue that the utilitarian framework is inadequate for this purpose: on the one hand, it is almost impossible to accurately predict the benefits of a study for all potential stakeholders; and on the other hand, harm inflicted on NHPs (and other animals) used in laboratory research is extensive despite the increasing efforts of ethics committees and the research community to address this. Although deontology and utilitarianism are both valid ethical frameworks, we advocate that a deontological approach is more suitable, since we arguably have moral duties to NHPs. We provide suggestions on how to ensure that research currently conducted in laboratory settings shifts towards approaches that abide by deontological principles. We assert that this would not impede reasonable scientific research.
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Affiliation(s)
- Constança Carvalho
- Centre for Philosophy of Science of the University of Lisbon, Department Animal Biology, Faculty of Sciences, University of Lisbon, Lisbon 1749-016, Portugal.
| | - Augusta Gaspar
- Catolica Research Center for Psychological, Family and Social Wellbeing (CRC-W), Universidade Católica Portuguesa, Palma de Cima, Lisboa 1649-023, Portugal.
| | - Andrew Knight
- Centre for Animal Welfare, Faculty of Humanities and Social Sciences, University of Winchester, Winchester SO22 4NR, UK.
| | - Luís Vicente
- Centre for Philosophy of Science of the University of Lisbon, Department Animal Biology, Faculty of Sciences, University of Lisbon, Lisbon 1749-016, Portugal.
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Temperature and depth evaluation of the in vitro effects of femtosecond laser on oral soft tissue, with or without air-cooling. Lasers Med Sci 2018; 34:649-658. [PMID: 30215183 DOI: 10.1007/s10103-018-2634-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/04/2018] [Indexed: 12/21/2022]
Abstract
Femtosecond laser is an effective and safe tool in many surgeries, but the studies of its effect on oral soft tissue ablation are insufficient. This study aimed to investigate the effect of soft tissue ablation with a 1030-nm femtosecond laser on temperature and depth. Twenty Sprague-Dawley rat tongue specimens were obtained and flat-mounted. The 1030-nm femtosecond laser was controlled by a computer system, with a set distance of 4.7 mm between the laser aperture and soft tissue surfaces. Ten specimens were ablated for > 1 min with or without air-cooling for temperature measurement, while the other 10 specimens were ablated for depth measurements, using the following parameters: (i) 3 W, 2000 mm/s; (ii) 3 W, 4000 mm/s; (iii) 5 W, 2000 mm/s; (iv) 5 W, 4000 mm/s; (v) 8 W, 2000 mm/s; (vi) 8 W, 4000 mm/s. Temperature changes were measured using a type-K thermocouple. The depth attained using different power and scanning speed settings was measured by a three-dimensional morphology measurement laser microscope. Laser power, scanning speed, and air-cooling effects were determined. Higher energy and lower speed induced higher temperatures (p < 0.05), which were significantly decreased by air-cooling (p < 0.05). The lowest ablation depth was obtained at 3 W and 4000 mm/s (72.63 ± 6.47 μm) (p < 0.05). The greatest incision depth was achieved at 8 W and 2000 mm/s (696.19 ± 35.37 μm), or 4000 mm/s (681.16 ± 55.65 μm) (p < 0.05). The 1030-nm femtosecond laser application demonstrates clinically acceptable ablation efficiency, without marked temperature damage, in a controlled manner.
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