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Vilbert M, Bocheux R, Georgeon C, Borderie V, Pernot P, Irsch K, Plamann K. A new method for in vivo assessment of corneal transparency using spectral-domain OCT. PLoS One 2023; 18:e0291613. [PMID: 37796869 PMCID: PMC10553212 DOI: 10.1371/journal.pone.0291613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 09/02/2023] [Indexed: 10/07/2023] Open
Abstract
Corneal transparency is essential to provide a clear view into and out of the eye, yet clinical means to assess such transparency are extremely limited and usually involve a subjective grading of visible opacities by means of slit-lamp biomicroscopy. Here, we describe an automated algorithm allowing extraction of quantitative corneal transparency parameters with standard clinical spectral-domain optical coherence tomography (SD-OCT). Our algorithm employs a novel pre-processing procedure to standardize SD-OCT image analysis and to numerically correct common instrumental artifacts before extracting mean intensity stromal-depth (z) profiles over a 6-mm-wide corneal area. The z-profiles are analyzed using our previously developed objective method that derives quantitative transparency parameters directly related to the physics of light propagation in tissues. Tissular heterogeneity is quantified by the Birge ratio Br and the photon mean-free path (ls) is determined for homogeneous tissues (i.e., Br~1). SD-OCT images of 83 normal corneas (ages 22-50 years) from a standard SD-OCT device (RTVue-XR Avanti, Optovue Inc.) were processed to establish a normative dataset of transparency values. After confirming stromal homogeneity (Br <10), we measured a median ls of 570 μm (interdecile range: 270-2400 μm). By also considering corneal thicknesses, this may be translated into a median fraction of transmitted (coherent) light Tcoh(stroma) of 51% (interdecile range: 22-83%). Excluding images with central saturation artifact raised our median Tcoh(stroma) to 73% (interdecile range: 34-84%). These transparency values are slightly lower than those previously reported, which we attribute to the detection configuration of SD-OCT with a relatively small and selective acceptance angle. No statistically significant correlation between transparency and age or thickness was found. In conclusion, our algorithm provides robust and quantitative measurements of corneal transparency from standard SD-OCT images with sufficient quality (such as 'Line' and 'CrossLine' B-scan modes without central saturation artifact) and addresses the demand for such an objective means in the clinical setting.
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Affiliation(s)
- Maëlle Vilbert
- Laboratory for Optics and Biosciences (LOB)— École Polytechnique, CNRS, INSERM, IPP, Palaiseau, France
- Vision Institute—CNRS, INSERM, Sorbonne University, Paris, France
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
| | - Romain Bocheux
- Laboratory for Optics and Biosciences (LOB)— École Polytechnique, CNRS, INSERM, IPP, Palaiseau, France
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
- Physical Chemistry Institute (ICP)—CNRS, University of Paris-Saclay, Orsay, France
| | - Cristina Georgeon
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
| | - Vincent Borderie
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
| | - Pascal Pernot
- Physical Chemistry Institute (ICP)—CNRS, University of Paris-Saclay, Orsay, France
| | - Kristina Irsch
- Vision Institute—CNRS, INSERM, Sorbonne University, Paris, France
- GRC 32, Transplantation et Thérapies Innovantes de la Cornée, Sorbonne Université, Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Paris, France
| | - Karsten Plamann
- Laboratory for Optics and Biosciences (LOB)— École Polytechnique, CNRS, INSERM, IPP, Palaiseau, France
- LOA—ENSTA Paris, École polytechnique, CNRS, IPP, Palaiseau, France
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Wang C, Qu L, Chen X, Zhou Q, Yang Y, Zheng Y, Zheng X, Gao L, Hao J, Zhu L, Pi B, Yang C. Poly(arylene piperidine) Quaternary Ammonium Salts Promoting Stable Long-Lived Room-Temperature Phosphorescence in Aqueous Environment. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2204415. [PMID: 35731029 DOI: 10.1002/adma.202204415] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/16/2022] [Indexed: 06/15/2023]
Abstract
Room-temperature phosphorescence (RTP) materials have garnered considerable research attention owing to their excellent luminescence properties and potential application prospects in anti-counterfeiting, information storage, and optoelectronics. However, several RTP systems are extremely sensitive to humidity, and consequently, the realization of long-lived RTP in water remains a formidable challenge. Herein, a feasible and effective strategy is presented to achieve long-lived polymeric RTP systems, even in an aqueous environment, through doping of synthesized polymeric phosphor PBHDB into a poly(methyl methacrylate) (PMMA) matrix. Compared to the precursor polymer PBN and organic molecule HDBP, a more rigid polymer microenvironment and electrostatic interaction are formed between the PMMA matrix and polymer PBHDB, which effectively reduce the nonradiative decay rate of triplet excitons and dramatically increase the phosphorescence intensity. Specifically, the phosphorescence lifetime of the PBHDB@PMMA film (1258.62 ms) is much longer than those of PBN@PMMA (674.20 ms) and HDBP@PMMA (1.06 ms). Most importantly, a bright-green afterglow can be observed after soaking the PBHDB@PMMA film in water for more than a month. The excellent water resistance and reversible response properties endow these systems with promising potential for dynamic information encryption even in water.
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Affiliation(s)
- Chang Wang
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Lunjun Qu
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Xiaohong Chen
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Qian Zhou
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Yan Yang
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Yan Zheng
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Xian Zheng
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Liang Gao
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Jinqiu Hao
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Lingyun Zhu
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Bingxue Pi
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
| | - Chaolong Yang
- School of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
- Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, 510640, China
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Dawood YF. Study of corneal endothelial cells in diabetic patients. AFRICAN VISION AND EYE HEALTH 2022. [DOI: 10.4102/aveh.v81i1.664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background: The cornea is the anterior transparent part of the eye. In addition to its optical and refractive function, it is an important protective structure.Aim: The aim of this study was to assess corneal endothelium (counts, morphology and structure) as well as corneal thickness of Type 2 diabetic participants.Setting: This is a hospital-based case–control study and was carried out at Ibn Al Haitham tertiary eye hospital in Baghdad, Iraq.Methods: The sample size was 240 eyes of 120 diabetic participants and 120 healthy participants. Non-contact specular microscopy was utilised to evaluate corneal endothelial cells, including endothelial cell density (ECD), coefficient of variation in cell area (CV), hexagonality (HEX) of cells as well as central corneal thickness (CCT).Results: The ECD was lower in the diabetic corneas (2584.87 ± 259.15 cell/mm2) compared with the healthy corneas (2717.56 ± 289.67 cell/mm2) (p = 0.017, statistically significant). Coefficient of variance (CV) was greater in the diabetic group (40.8 ± 4.17) as opposed to the group with healthy corneas (37.3 ± 2.89) (p = 0.019, statistically significant). The corneas of the diabetic group showed lower hexagonality (44.36% ± 9.87%) compared with the healthy corneas (59.35% ± 9.67%) (p 0.001, statistically significant). Furthermore, the corneas of the diabetic group had greater central thickness (581.1 ± 32.4 µm) when compared with the control group (511.8 ± 29.8 µm), (p 0.001, statistically significant). No correlation was found between the severity level of diabetic retinopathy and corneal endothelial pathological alterations.Conclusion: Long-term poorly controlled glycaemia has a remarkable impact on corneal endothelium (counts, morphology and structure) as well as corneal thickness.
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Dawood YF, Issa AF, Faraj ES. Impact of surgical experience on early post-operative regional corneal thickness after phacoemulsification. AFRICAN VISION AND EYE HEALTH 2021. [DOI: 10.4102/aveh.v80i1.572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Background: Currently, phacoemulsification is a very common cataract surgical procedure in which the lens is emulsified and aspirated from the eye through a small corneal incision.Aim: To compare early regional corneal thickness changes following phacoemulsification done by experienced surgeons versus trainee surgeons.Setting: A prospective cohort study was done at Ibn Al Haitham tertiary eye hospital in Baghdad, Iraq.Methods: The data were collected for 5 months, from 01 March 2018 until 31 July 2018. Adult patients undergoing phacoemulsification and intraocular lens surgery were prospectively evaluated and divided into two groups. Group 1 comprised those operated by experienced surgeons, whilst Group 2 patients were operated by trainee surgeons. Slit lamp examination and endothelial specular microscopy were assessed with the measurement of central corneal thickness (CCT) and peripheral corneal thickness (PCT), using Scheimpflug imaging (Pentacam).Results: There was a significant statistical difference in post-operative CCT between Groups 1 and 2, being 596.72 ± 50.69 µm compared to 631.54 ± 67.84 µm in Groups 1 and 2, respectively, with a mean difference of 34.82 µm (p = 0.000). More difference was observed in post-operative PCT (148.38 µm) as it was 734.8 ± 88.55 µm in the experienced group, compared to 883.18 ± 128.43 µm in the trainee group (p = 0.005).Conclusion: Phacoemulsification done by trainee surgeons was associated with higher CCT and PCT.
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Peterson JC, Arrieta E, Ruggeri M, Silgado JD, Mintz KJ, Weisson EH, Leblanc RM, Kochevar I, Manns F, Parel JM. Detection of singlet oxygen luminescence for experimental corneal rose bengal photodynamic antimicrobial therapy. BIOMEDICAL OPTICS EXPRESS 2021; 12:272-287. [PMID: 33520385 PMCID: PMC7818961 DOI: 10.1364/boe.405601] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/19/2020] [Accepted: 10/25/2020] [Indexed: 05/03/2023]
Abstract
Rose bengal photodynamic antimicrobial therapy (RB-PDAT) treats corneal infection by activating rose bengal (RB) with green light to produce singlet oxygen (1O2). Singlet oxygen dosimetry can help optimize treatment parameters. We present a 1O2 dosimeter for detection of 1O2 generated during experimental RB-PDAT. The system uses a 520 nm laser and an InGaAs photoreceiver with bandpass filters to detect 1O2 luminescence during irradiation. The system was validated in RB solutions and ex vivo in human donor eyes. The results demonstrate the feasibility of 1O2 dosimetry in an experimental model of RB-PDAT in the cornea.
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Affiliation(s)
- Jeffrey C Peterson
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Dr, Coral Gables, FL 33146, USA
- Miller School of Medicine, University of Miami, 1600 NW 10th Ave #1140, Miami, FL 33136, USA
| | - Esdras Arrieta
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
| | - Marco Ruggeri
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Dr, Coral Gables, FL 33146, USA
| | - Juan D Silgado
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
| | - Keenan J Mintz
- Department of Chemistry, University of Miami, 1301 Memorial Dr, Coral Gables, FL 33146, USA
| | - Ernesto H Weisson
- Miller School of Medicine, University of Miami, 1600 NW 10th Ave #1140, Miami, FL 33136, USA
| | - Roger M Leblanc
- Department of Chemistry, University of Miami, 1301 Memorial Dr, Coral Gables, FL 33146, USA
| | - Irene Kochevar
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, 50 Blossom Street, Boston, MA 02114, USA
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Dr, Coral Gables, FL 33146, USA
- Miller School of Medicine, University of Miami, 1600 NW 10th Ave #1140, Miami, FL 33136, USA
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, 1251 Memorial Dr, Coral Gables, FL 33146, USA
- Anne Bates Leach Eye Center, Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 900 NW 17th St, Miami, FL 33136, USA
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Dawood YF, Issa AF, Faraj ES. Impact of surgical experience on early post-operative regional corneal thickness after phacoemulsification. AFRICAN VISION AND EYE HEALTH 2020. [DOI: 10.4102/aveh.v79i1.572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Varga Z, Bergin C, Roy S, Nicolas M, Tschuor P, Majo F. Scanning Electronic Microscopy Evaluation of the Roughness of the Stromal Bed After Deep Corneal Cut with the LDV Femtosecond Laser (Z6) (Ziemer) and the ONE Microkeratome (Moria). Curr Eye Res 2016; 41:1302-1309. [PMID: 26881295 DOI: 10.3109/02713683.2015.1119281] [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] [Indexed: 11/13/2022]
Abstract
PURPOSE To compare the stromal bed surface quality and the accuracy of dissection depth after deep lamellar cuts using the Leonardo Da Vinci (LDV) femtosecond laser (Z6) and the ONE Microkeratome. METHODS Deep lamellar cuts were performed on nine human donor corneoscleral buttons: five with the LDV femtosecond (FS) laser (Z6) (Ziemer) and four with the ONE Microkeratome (MK) (Moria). Corneal thickness was measured with ultrasound pachymetry before and after the dissection. The Stromal bed quality was evaluated using light microscopy (n = 4) and scanning electron microscopy (SEM) (n = 9). The surface roughness on SEM images was graded on the scale of 1 (smoothest) to 5 (roughest) by four observers, blinded to the method used. Particle analysis on the SEM images was performed in order to have an objective measure of smoothness. RESULTS The achieved dissection depth using the FS laser was 496.4 ± 46.4 µm when attempting 500 µm and 474 ± 60 µm with the microkeratome when attempting 350 µm. Histological evaluation of the corneoscleral buttons by both light and electron microscopy showed significantly smoother surface using the FS laser compared to the microkeratome. There were fewer and smaller particles observed in the SEM images of FS laser cut buttons (p < 0.001).The average observer based score of anterior surface roughness (50×) was 2.2 for the FS laser and 3.9 for the microkeratome dissections (p < 0.001). CONCLUSIONS The LDV femtosecond laser (Z6) platform is capable of creating deep corneal lamellar dissection with smoother surface quality and with more predictable cut depth as compared to the One Microkeratome.
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Affiliation(s)
- Zsolt Varga
- a Department of Ophthalmology , University of Lausanne, Fondation Asile des Aveugles , Lausanne , Switzerland.,b Department of Clinical Neuroscience , University Hospital of Geneva , Geneva , Switzerland
| | - Ciara Bergin
- a Department of Ophthalmology , University of Lausanne, Fondation Asile des Aveugles , Lausanne , Switzerland
| | | | - Michael Nicolas
- a Department of Ophthalmology , University of Lausanne, Fondation Asile des Aveugles , Lausanne , Switzerland
| | - Patrizia Tschuor
- a Department of Ophthalmology , University of Lausanne, Fondation Asile des Aveugles , Lausanne , Switzerland
| | - François Majo
- a Department of Ophthalmology , University of Lausanne, Fondation Asile des Aveugles , Lausanne , Switzerland
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Reliability of Pentacam HR Thickness Maps of the Entire Cornea in Normal, Post-Laser In Situ Keratomileusis, and Keratoconus Eyes. Am J Ophthalmol 2016; 162:74-82.e1. [PMID: 26556008 DOI: 10.1016/j.ajo.2015.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/03/2015] [Accepted: 11/03/2015] [Indexed: 11/21/2022]
Abstract
PURPOSE To measure the repeatability and reproducibility of Pentacam HR system thickness maps for the entire cornea in normal, post-laser in situ keratomileusis (post-LASIK), and keratoconus (KC) eyes. DESIGN Reliability study. METHODS Sixty normal subjects (60 eyes), 30 post-LASIK subjects (60 eyes), and 14 KC patients (27 eyes) were imaged with the Pentacam HR system by 2 well-trained operators. For pachymetry the cornea was divided into 4 zones: a central zone (2-mm diameter) and concentric pericentral zone (2-5 mm), transitional zone (5-7 mm), and peripheral zone (7-10 mm). The 3 concentric zones were subdivided into 8 sectors. Intraobserver repeatability and interobserver reproducibility of entire corneal thickness maps were tested by the repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement. RESULTS From central to peripheral zones, the precision of corneal thickness measurements became gradually smaller. Central zone repeatability and reproducibility were the best in the normal, post-LASIK, and KC groups. The peripheral superior sectors showed poorer repeatability and reproducibility for all subjects. The intraobserver repeatability and interobserver reproducibility for all zones were ≤19.3 μm, ≤22.1 μm, and ≤20.7 μm, in the normal, post-LASIK, and KC groups, respectively. The intraobserver and interobserver coefficients of variation for all zones were ≤1.3%, ≤1.6%, and ≤1.6% for all 3 groups. CONCLUSIONS Pentacam HR system pachymetry of the entire cornea provided good precision in normal, post-LASIK, and KC corneas. Thickness measurements in the peripheral cornea should be interpreted with caution in abnormal corneas after surgery or with diseases.
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Linke SJ, Ren L, Frings A, Steinberg J, Wöllmer W, Katz T, Reimer R, Hansen NO, Jowett N, Richard G, Dwayne Miller RJ. [Perspectives of laser-assisted keratoplasty: current overview and first preliminary results with the picosecond infrared laser (λ = 3 µm)]. Ophthalmologe 2015; 111:523-30. [PMID: 24942118 DOI: 10.1007/s00347-013-2995-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND This article provides a review of the current state of laser-assisted keratoplasty and describes a first proof of concept study to test the feasibility of a new mid-infrared (MIR) picosecond laser to perform applanation-free corneal trephination. METHODS The procedure is based on a specially adapted laser system (PIRL-HP2-1064 OPA-3000, Attodyne, Canada) which works with a wavelength of 3,000 ± 90 nm, a pulse duration of 300 ps and a repetition rate of 1 kHz. The picosecond infrared laser (PIRL) beam is delivered to the sample by a custom-made optics system with an implemented scanning mechanism. Corneal specimens were mounted on an artificial anterior chamber and subsequent trephination was performed with the PIRL under stable intraocular pressure conditions. RESULTS A defined corneal ablation pattern, e.g. circular, linear, rectangular or disc-shaped, can be selected and its specific dimensions are defined by the user. Circular and linear ablation patterns were employed for the incisions in this study. Linear and circular penetrating PIRL incisions were examined by macroscopic inspection, histology, confocal microscopy and environmental scanning electron microscopy (ESEM) for characterization of the incisional quality. Using PIRL reproducible and stable incisions could be made in human and porcine corneal samples with minimal damage to the surrounding tissue. CONCLUSION The PIRL laser radiation in the mid-infrared spectrum with a wavelength of 3 µm is exactly tuned to one of the dominant vibrational excitation bands of the water molecule, serves as an effective tool for applanation-free corneal incision and might broaden the armamentarium of corneal transplant surgery.
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Affiliation(s)
- S J Linke
- Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Eppendorf (UKE), Martinistr. 52, 20246, Hamburg, Deutschland,
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A new technology for applanation free corneal trephination: the picosecond infrared laser (PIRL). PLoS One 2015; 10:e0120944. [PMID: 25781907 PMCID: PMC4363595 DOI: 10.1371/journal.pone.0120944] [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: 09/08/2014] [Accepted: 01/29/2015] [Indexed: 11/19/2022] Open
Abstract
The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 μm are efficient for obtaining applanation-free deep cuts on porcine corneas.
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11
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Plamann K. [Importance of wavelength for ultrashort laser pulses in healthy and pathological corneas]. Ophthalmologe 2014; 111:514-22. [PMID: 24942117 DOI: 10.1007/s00347-013-2992-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND A study on the role of laser wavelength in keratoplasty assisted by ultrashort pulse lasers is presented. MATERIAL AND METHODS This article gives a summary of the principal physical mechanisms contributing to the transparency of healthy corneas and presents transparency measurements as well as laboratory experiments on tissue with lasers at different wavelengths. RESULTS The transparency of a healthy cornea is strongly related to its regular structure at micrometer and nanometer length scales. Many indications for keratoplasty are associated with a perturbation of this structure and therefore with a sometimes strongly reduced tissue transparency. This explains the often unsatisfactory results obtained when using ultrashort pulse lasers for the procedure. Theoretical considerations and laboratory experiments show that the light scattering processes responsible for the loss in laser beam quality depend strongly on wavelength and the use of wavelengths longer than those presently used allows these processes to be almost completely eliminated. The use of a spectral transparency window close to 1.65 µm is suggested. CONCLUSION The use of laser wavelengths close to 1.65 µm represents an interesting alternative for the improvement of keratoplasty assisted by ultrashort pulse lasers.
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Affiliation(s)
- K Plamann
- Laboratoire d'Optique Appliquée, ENSTA ParisTech - École Polytechnique - CNRS UMR 7639, École Nationale Supérieure de Techniques Avancées (ENSTA ParisTech), 828 Boulevard des Maréchaux, 91762, Palaiseau cedex, Frankreich,
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Preparing uniform-thickness corneal endothelial grafts from donor tissues using a non-amplified femtosecond laser. PLoS One 2013; 8:e83185. [PMID: 24340090 PMCID: PMC3855481 DOI: 10.1371/journal.pone.0083185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 11/08/2013] [Indexed: 11/24/2022] Open
Abstract
Corneal grafts for Descemet’s Stripping Automated Endothelial Keratoplasty are commonly prepared using mechanical microkeratomes. However, the cuts produced in such way render corneal lenticules that are thinner centrally than peripherally, thus inducing a hyperopic shift. Here we describe a novel device for preparing donor corneal grafts, in which a single low-energy femtosecond laser system is used as both a light source for optical coherence tomography and for cutting the graft illuminating from the endothelial side. The same laser is first utilized to obtain three-dimensional optical coherence tomography images of the donor tissue for guiding the dissection and obtaining grafts of uniform thickness with no applanation or contact. This device allows an optimal procedure for preparing consistently thin posterior grafts for transplantation.
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Posterior lamellar graft preparation: a prospective review from an eye bank on current and future aspects. J Ophthalmol 2013; 2013:769860. [PMID: 23819041 PMCID: PMC3683473 DOI: 10.1155/2013/769860] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/30/2013] [Accepted: 05/08/2013] [Indexed: 11/17/2022] Open
Abstract
Descemet membrane endothelial keratoplasty (DMEK) is a corneal surgical technique which selectively replaces the damaged posterior part of the cornea with a healthy donor graft retaining the rest of the tissue intact. There is a need to validate and standardize the donor tissue before grafting due to certain issues that can lead to consequences such as graft failure due to poor endothelial cell count, higher mortality, detachment of the graft, or increased surgical expenses, time, and effort. Thus, prospective potential surgeons and eye banks should now aim at developing new improved surgical techniques in order to prepare the best suited, validated, precut, preloaded, and easy to transplant tissue to reduce pre- and postsurgical complications. This could be achieved by defining parameters like graft thickness, accepted mortality threshold of the endothelial cells, and behavior of grafts during preservation and transportation along with using more sophisticated instruments like microkeratome and femtosecond lasers for graft preparation. Thus, a rapport between the eye banks and the surgeons along with the advanced instruments can overcome this challenge to find the best possible solution for endothelial keratoplasty (EK).
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Casadessus O, Georges G, Lamoine LS, Deumié C, Hoffart L. Light scattering from edematous human corneal grafts' microstructure: experimental study and electromagnetic modelization. BIOMEDICAL OPTICS EXPRESS 2012; 3:1793-1810. [PMID: 22876345 PMCID: PMC3409700 DOI: 10.1364/boe.3.001793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 03/31/2012] [Accepted: 04/29/2012] [Indexed: 06/01/2023]
Abstract
Along with the lens, the cornea is the only transparent tissue in the human body. However, the development of an edema involves structural disturbances increasing light scattering and leading to the opacification of the cornea. Several mechanisms of transparency loss have been studied in the literature, but the whole phenomenon is complex and the part played by each scatterer is still unclear. We propose here to study human corneal grafts combining microscopic OCT imagery with far-field measurement of the scattered light in the reflected half-space. We introduce afterwards numerical calculations based on electromagnetic equations solved with first order approximation to link the observed microscopic-scale structural modifications with the intensity level of the scattered light, and to try and quantify the relationship between them.
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Affiliation(s)
- Olivier Casadessus
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Gaëlle Georges
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Laure Siozade Lamoine
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Carole Deumié
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Louis Hoffart
- Service d’Ophtalmologie de l’Hôpital de la Timone, APHM, Université d’Aix-Marseille, 264 rue Saint Pierre, 13 385 Marseille Cedex 5, France
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15
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Peyrot DA, Lefort C, Steffenhagen M, Mansuryan T, Ducourthial G, Abi-Haidar D, Sandeau N, Vever-Bizet C, Kruglik SG, Thiberville L, Louradour F, Bourg-Heckly G. Development of a nonlinear fiber-optic spectrometer for human lung tissue exploration. BIOMEDICAL OPTICS EXPRESS 2012; 3:840-53. [PMID: 22567579 PMCID: PMC3342191 DOI: 10.1364/boe.3.000840] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 03/23/2012] [Accepted: 03/23/2012] [Indexed: 05/12/2023]
Abstract
Several major lung pathologies are characterized by early modifications of the extracellular matrix (ECM) fibrillar collagen and elastin network. We report here the development of a nonlinear fiber-optic spectrometer, compatible with an endoscopic use, primarily intended for the recording of second-harmonic generation (SHG) signal of collagen and two-photon excited fluorescence (2PEF) of both collagen and elastin. Fiber dispersion is accurately compensated by the use of a specific grism-pair stretcher, allowing laser pulse temporal width around 70 fs and excitation wavelength tunability from 790 to 900 nm. This spectrometer was used to investigate the excitation wavelength dependence (from 800 to 870 nm) of SHG and 2PEF spectra originating from ex vivo human lung tissue samples. The results were compared with spectral responses of collagen gel and elastin powder reference samples and also with data obtained using standard nonlinear microspectroscopy. The excitation-wavelength-tunable nonlinear fiber-optic spectrometer presented in this study allows performing nonlinear spectroscopy of human lung tissue ECM through the elastin 2PEF and the collagen SHG signals. This work opens the way to tunable excitation nonlinear endomicroscopy based on both distal scanning of a single optical fiber and proximal scanning of a fiber-optic bundle.
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Affiliation(s)
- Donald A. Peyrot
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Claire Lefort
- Faculté des Sciences et Techniques, Univ. Limoges, F-87060 Limoges, France
- XLIM, UMR CNRS 6172, F-87060 Limoges, France
| | - Marie Steffenhagen
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Tigran Mansuryan
- Faculté des Sciences et Techniques, Univ. Limoges, F-87060 Limoges, France
- XLIM, UMR CNRS 6172, F-87060 Limoges, France
| | - Guillaume Ducourthial
- Faculté des Sciences et Techniques, Univ. Limoges, F-87060 Limoges, France
- XLIM, UMR CNRS 6172, F-87060 Limoges, France
| | - Darine Abi-Haidar
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Nicolas Sandeau
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Christine Vever-Bizet
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Sergei G. Kruglik
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
| | - Luc Thiberville
- Clinique de pneumologie, CHU Rouen, F-76000 Rouen, France
- Laboratoire LITIS-QuantIF EA 4108, Rouen Univ., F-76000 Rouen, France
| | - Frédéric Louradour
- Faculté des Sciences et Techniques, Univ. Limoges, F-87060 Limoges, France
- XLIM, UMR CNRS 6172, F-87060 Limoges, France
| | - Geneviève Bourg-Heckly
- UPMC Univ. Paris 06, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
- CNRS, FRE 3231, Laboratoire Jean Perrin, F-75005, Paris, France
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16
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Plamann K, Alahyane F, Aptel F, Bayleyegn M, Courjaud A, Crotti C, Deloison F, Druon F, Dubois A, Georges P, Hanna M, Kowalczuk L, Legeais JM, Marciano T, Mottay E, Savoldelli M. Nouvel outil pour la chirurgie du glaucome assistée par laser femtoseconde et tomographie de cohérence optique. Ing Rech Biomed 2012. [DOI: 10.1016/j.irbm.2012.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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17
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Développement d’un endomicroscope non linéaire pour l’observation in vivo in situ de la matrice extracellulaire des tissus pulmonaires. Ing Rech Biomed 2012. [DOI: 10.1016/j.irbm.2012.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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