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D Robert Iskander, Alejandra Consejo, Jedrzej Solarski, Karol Karnowski, Maciej Wojtkowski; Corneal properties of Glaucoma based on Scheimpflug light intensity distribution. Invest. Ophthalmol. Vis. Sci. 2020;61(7):4716.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the properties of corneal microstructure in vivo of glaucomatous and healthy control eyes.
Eleven eyes of glaucoma patients and 14 of control participants with matching age, underwent measurements with Corvis ST (Oculus, Wetzlar, Germany), a noncontact air-puff tonometer that uses a high-speed Scheimpflug (SCH) camera to depict a cross-section of the cornea during deformation. A set of 140 images (ca. 32 ms) acquired per measurement were exported for further analysis that consisted of two steps: corneal segmentation and statistical modeling of pixel intensity distribution. The pixel intensity in the region of interest (ROI) encompassing corneal stroma was approximated with Weibull distribution, the parameters of which (α and β) can be used to describe the corneal microstructure. Time series of those parameters were analyzed and the relationship between them evaluated when the cornea was in a convex and a concave position.
The parameters α(t) and β(t) were found to be good discriminators between glaucomatous and control eyes (Fig 1A), with statistically significant differences for both α(t) (Mann-Whitney U-test, p < 0.05/N (N=140, Bonferroni)) and β(t) (Mann-Whitney U-test, p < 0.05/N (N=140, Bonferroni)). Relationship between α and β parameters with the cornea in concave state was found to be a better discriminator than when the cornea is in convex state (Fig 1B).
We investigated for the first time, the usefulness of SCH images of cornea to discriminate glaucomatous from control eyes. It is noted that the parameters extracted from static images have the potential to perform this differentiation without inducing corneal deformation.
This is a 2020 ARVO Annual Meeting abstract.
(A) Mean values of the dynamic evolution of parameters α(t) and β(t), for 11 glaucomatous participants, in red, and 14 control participants, in blue. (B) Mean values of α(t) and β(t) parameters when the cornea is in concave state prior to air-puff (left hand side) and when the cornea is in convex state during the air-puff (down right hand side). Data corresponding to cornea in concave state is zoomed, including error bars corresponding to one standard deviation from the mean.
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