Cell viability and shock wave amplitudes in the endothelium of porcine cornea exposed to ultrashort laser pulses.
Details
Serval ID
serval:BIB_2BEE0173E74A
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Cell viability and shock wave amplitudes in the endothelium of porcine cornea exposed to ultrashort laser pulses.
Journal
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie
ISSN
1435-702X (Electronic)
ISSN-L
0721-832X
Publication state
Published
Issued date
05/2017
Peer-reviewed
Oui
Volume
255
Number
5
Pages
945-953
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Publication Status: ppublish
Abstract
Some forms of keratoplasty assisted by ultrashort-pulse lasers require performing laser cuts close to the endothelium, which requires the knowledge of "safe" values concerning incision depth and pulse energy preserving endothelial cell viability. Our study aims to determine the thresholds for cell death in porcine corneas exposed to ultrashort laser pulses, in terms of laser pulse energy and nearness of the impacts to the endothelium.
Using a laboratory laser set-up, lamellar cuts were induced while varying pulse energies and distances from the endothelium. A fluorescent staining protocol was used to determine the percentage of surviving endothelial cells. Numerical simulations of the Euler equations for compressible fluids provided pressure level and axial and radial pressure gradient estimates at the endothelium.
Ninety percent of the endothelial cells survived when using 16.5 μJ pulses no closer than 200 μm to the endothelium, or pulses not exceeding 2 μJ at a distance of 50 μm. The comparison of the observed percentage of surviving cells with the estimates of the shock wave amplitudes and gradients generated by the laser pulses yielded cell death thresholds at amplitudes in the megapascal range, or gradients of the order of 108 Pa/m.
Our results provide limits in terms of pulse energy and distance of the incision from the endothelium within which endothelial cell viability is preserved. Current forms of corneal laser surgery are compatible with these limits. However, these limits will need to be considered for the development of future laser routines working in close proximity to the endothelium.
Using a laboratory laser set-up, lamellar cuts were induced while varying pulse energies and distances from the endothelium. A fluorescent staining protocol was used to determine the percentage of surviving endothelial cells. Numerical simulations of the Euler equations for compressible fluids provided pressure level and axial and radial pressure gradient estimates at the endothelium.
Ninety percent of the endothelial cells survived when using 16.5 μJ pulses no closer than 200 μm to the endothelium, or pulses not exceeding 2 μJ at a distance of 50 μm. The comparison of the observed percentage of surviving cells with the estimates of the shock wave amplitudes and gradients generated by the laser pulses yielded cell death thresholds at amplitudes in the megapascal range, or gradients of the order of 108 Pa/m.
Our results provide limits in terms of pulse energy and distance of the incision from the endothelium within which endothelial cell viability is preserved. Current forms of corneal laser surgery are compatible with these limits. However, these limits will need to be considered for the development of future laser routines working in close proximity to the endothelium.
Keywords
Animals, Cell Death, Cell Survival, Corneal Surgery, Laser/methods, Endothelium, Corneal/surgery, Endothelium, Corneal/ultrastructure, Microscopy, Electron, Scanning, Models, Animal, Swine, Tomography, Optical Coherence, Cell viability, Cornea, Endothelium, Keratoplasty, Laser surgery, Ultrashort pulse
Pubmed
Web of science
Create date
07/12/2017 9:17
Last modification date
20/08/2019 13:11