Forward scattering properties of corneal haze.

Details

Serval ID
serval:BIB_0EB43FCD2592
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Forward scattering properties of corneal haze.
Journal
Optometry and vision science
Author(s)
De Brouwere D., Ginis H., Kymionis G., Naoumidi I., Pallikaris I.
ISSN
1538-9235 (Electronic)
ISSN-L
1040-5488
Publication state
Published
Issued date
09/2008
Peer-reviewed
Oui
Volume
85
Number
9
Pages
843-848
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
Corneal haze is a well-known pathology associated with decreased corneal transparency and increased ocular scattering. Clinically, haze is typically estimated as the amount of backscattered light observed in a slit lamp examination while the small angle forward scattering cannot be directly observed. It was the purpose of this study to demonstrate a single-pass technique to objectively measure forward scattering properties of excised rabbit corneas.
Six rabbits (twelve eyes) were used in this study. All eyes underwent photorefractive keratectomy for -4 D in a 6 mm ablation zone. Seven weeks later, the rabbits were examined under general anesthesia. All eyes expressed mild to severe haze. A purposely-developed single pass optical setup was used both to estimate the angular distribution and fraction of forward light scattering in excised rabbit corneas. Moreover, subjective clinical corneal haze evaluation was performed as well as corneal confocal microscopy of all corneas. Finally, the corneas were histopathologically examined.
Light scattering in the rabbit corneas followed a narrow forward peaked distribution. A new parameter, Ballistic Ratio, was introduced to represent a parameter for absolute quantification of forward light scatter, corresponding to the power ratio of the radiation that is not scattered by each sample. A negative correlation between clinically subjective corneal haze and forward scatter (Pearson's Coefficient = -0.23) was found, which suggests the relation between increased forward and backward scatter. Activated myofibroblasts, collagen irregularities and vacuoles present in a sub-epithelial layer over the treated area of the cornea had characteristic dimensions in accordance to the measured scatter distribution.
Corneal light scatter associated with the increased amount of haze after excimer laser ablation has a narrowly forward distribution that can be attributed to the subepithelial structures observed in treated corneas.
Keywords
Animals, Cornea/physiopathology, Corneal Opacity/etiology, Corneal Opacity/physiopathology, Light, Male, Photorefractive Keratectomy/adverse effects, Rabbits, Scattering, Radiation, Vision Disorders/etiology
Pubmed
Web of science
Create date
02/10/2019 8:49
Last modification date
06/10/2019 5:26
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