Microstructural changes in sclera under thermo-mechanical effect of 1.56 µm laser radiation increasing transscleral humor outflow
Background and Objectives Pores in the sclera are a candidate pathway for aqueous transport and therefore can be utilized to decrease the intraocular pressure (IOP) in glaucomatous eyes. Since pore formation is a well‐known mechanism for stress relaxation in solids, laser‐induced creation of pores i...
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Published in | Lasers in surgery and medicine Vol. 46; no. 1; pp. 46 - 53 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Blackwell Publishing Ltd
01.01.2014
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Subjects | |
Online Access | Get full text |
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Summary: | Background and Objectives
Pores in the sclera are a candidate pathway for aqueous transport and therefore can be utilized to decrease the intraocular pressure (IOP) in glaucomatous eyes. Since pore formation is a well‐known mechanism for stress relaxation in solids, laser‐induced creation of pores in cartilage increases hydraulic permeability and promotes tissue regeneration. The aim of this paper is to demonstrate the thermo‐mechanical effect of non‐destructive laser irradiation on microstructural changes in sclera, in particular pore formation, resulting in substantial increase of water permeability of eye tissues that can be a novel approach to normalize the IOP.
Materials and Methods
Experiments were performed ex vivo on eight eyes of four mini‐pigs and in vivo on eight eyes of four rabbits using pulse repetitive laser radiation of 1.56 µm in wavelength. Twenty laser spots of 0.6 mm in diameter with laser settings (power 0.9 W, pulse duration of 200 milliseconds, pulse repetition rate of 2 Hz) resulting in substantial increase of sclera hydraulic permeability were applied on the sclera at 1–2 mm from the eye limb. Sclera and underlying structures (choroid and ciliary body) of the rabbits' eyes were examined histologically in 1 and 45 days after laser irradiation, atomic force microscope (AFM) was applied before and after laser irradiation.
Results
Histological and AFM examinations have clearly recognized laser‐assisted stable structural alterations: rarefication of the collagen structure in the laser irradiated zone and formation of sub‐micron pores. Laser‐induced alterations in the structure of ciliary bodies were small in size and mainly reversible. We have proposed a possible mechanism of the arising pores stabilization due to formation of small stable gas bubbles in sclera tissue.
Conclusions
It is shown, for the first time, that thermo‐mechanical effect of pulse repetitive laser irradiation results in pores formation in sclera. That can be a basis of a novel, safe, and effective technique for IOP normalization due to enhancing of uveoscleral outflow under non‐destructive laser irradiation of the sclera. Lasers Surg. Med. 46:46–53, 2014. © 2013 Wiley Periodicals, Inc. |
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Bibliography: | ArticleID:LSM22202 istex:4E0B76BE57C1D202CC67D8AE2BC867FF9E43785B ark:/67375/WNG-FGZL2HC8-K Russian Foundation for Basic Research (RFBR) Karlsruhe Nano Micro Facility (KNMF) Karlsruhe Institute of Technology (KIT) ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0196-8092 1096-9101 |
DOI: | 10.1002/lsm.22202 |