In-vivo imaging of the palisades of Vogt and the limbal crypts with sub-micrometer axial resolution optical coherence tomography.

Kostadinka Bizheva,Zohreh Hosseinaee,Benjamin Maclellan,Erik Mason,Luigina Sorbara,Denise Hileeto,Bingyao Tan

doi:10.1364/boe.8.004141

Abstract

A research-grade OCT system was used to image in-vivo and without contact with the tissue, the cellular structure and microvasculature of the healthy human corneo-scleral limbus. The OCT system provided 0.95 µm axial and 4 µm (2 µm) lateral resolution in biological tissue depending on the magnification of the imaging objective. Cross-sectional OCT images acquired tangentially from the inferior limbus showed reflective, loop-like features that correspond to the fibrous folds of the palisades of Vogt (POV). The high OCT resolution allowed for visualization of individual cells inside the limbal crypts, capillaries extending from the inside of the POV's fibrous folds and connecting to a lateral grid of micro-vessels located in the connective tissue directly below the POV, as well as reflections from individual red blood cells inside the capillaries. Difference in the reflective properties of the POV was observed among subjects of various pigmentation levels of the POV. Morphological features observed in the high resolution OCT images correlated well with histology. The ability to visualize the limbal morphology and microvasculature in-vivo at cellular level can aid the diagnostics and treatment of limbal stem cell dysfunction and dystrophies.

Highlights

The corneo-scleral limbus is about 1.5 mm wide transitional region of tissue that separates anatomically the peripheral cornea from the conjunctiva
We present for the first time, cross-sectional and volumetric OCT images of the cellular structure of the limbal crypts and the palisades of Vogt (POV), that were acquired in-vivo from healthy human subjects without contact between the OCT imaging probe and the limbal tissue
A volumetric image of the inferior POV is presented in Fig. 1(C), where the top edge of the image corresponds to the peripheral cornea

Summary

Introduction

The corneo-scleral limbus is about 1.5 mm wide transitional region of tissue that separates anatomically the peripheral cornea from the conjunctiva. The limbus has a rich and complex morphology [1,2] with dense innervations [3] and vascularization [4,5], that provides an unique environment for housing the corneal epithelial stem cells [6,7]. The limbal epithelial crypts house stem cells, which play a key role in the regeneration of the corneal epithelium [6,7]. The scleral part of the limbus contains both a rich vascular network responsible for oxygen and nutritional supply of the peripheral cornea, and a complex aqueous outflow system (Schlemm’s canal, trabecular meshwork), responsible for the aqueous humor circulation and waste management [4,5,8]

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Discussion

Conclusion