Clinical features and corneal optical anisotropies in a rabbit model of limbal stem cell deficiency

Abstract

These results suggest that rabbit models of limbal stem cell deficiency must be rigorously screened for use in preclinical studies to ensure experimental homogeneity because protocols used to create limbal stem cell deficiency could be not associated with good intra-laboratory reproducibility of clinical features. Limbal stem cell deficiency, as induced herein, altered the optical anisotropic properties of the corneal stroma. Such alterations are indicative of changes in collagen packing and the spatial orientation of glycosaminoglycan chains from proteoglycans. Knowledge of these changes is important to potentiate strategies aimed at restoring the morphofunctional integrity of the corneal stroma affected by limbal stem cell deficiency.

Birefringence analysis of collagen supraorganization in cat corneas with tropical keratopathy

“…The corneal stromal supraorganization can be analyzed using polarized light‐based imaging techniques, as the collagen fibers present in the stroma are highly birefringent 12–14,33–38 . Birefringence is a phenomenon that occurs when a monochromatic light beam splits into two rays after interaction with the collagen fibers 12,33 .…”

“…The corneal stromal supraorganization can be analyzed using polarized light-based imaging techniques, as the collagen fibers present in the stroma are highly birefringent. [12][13][14][33][34][35][36][37][38] Birefringence is a phenomenon that occurs when a monochromatic light beam splits into two rays after interaction with the collagen fibers. 12,33 These rays, known as extraordinary and ordinary, have different refractive indices, with the extraordinary ray (ne) having a higher refractive index and traveling parallel to the long axis of the collagen fiber, while the ordinary ray (no) has a lower refractive index and travels perpendicular to the fiber axis.…”

What can Biophotonics tell us about the Structure and Physiology of the Cornea?

“…Birefringence can be defined as the ability of the cornea to decompose the light into two orthogonally polarized rays with different velocities [8,10]. The vectors experience a phase shift relative to each another, which is expressed by the equation: δ = (2π/λ) x LΔ n , where δ is the phase difference between propagating orthogonal polarizations, λ is the photon wavelength, L is the thickness of the sample, and ∆ n is the difference in the refractive indices between the two optical axes of the sample.…”

“…The vectors experience a phase shift relative to each another, which is expressed by the equation: δ = (2π/λ) x LΔ n , where δ is the phase difference between propagating orthogonal polarizations, λ is the photon wavelength, L is the thickness of the sample, and ∆ n is the difference in the refractive indices between the two optical axes of the sample. L∆ n is known as the optical path difference or retardation [8,10].…”