Cellular resolution corneal imaging with extended imaging range.

Lulu Wang,Qiaozhou Xiong,En Bo,Linbo Liu,Xianghong Wang,Jun Xie,Xin Ge,Xinyu Liu,Si Chen,Xuan Wu,Nanshuo Wang,Xiaojun Yu

doi:10.1364/oe.27.001298

Abstract

Current optical coherence tomography (OCT) technology, which is used for imaging the eye's anterior segment, has been established as a clinical gold standard for the diagnosis of corneal diseases. However, the cellular resolution level information that is critical for many clinical applications is still not available. The major technical challenges toward cellular resolution OCT imaging are the limited ranging depth and depth of focus (DOF). In this work, we present a novel ultrahigh resolution OCT system that achieves an isotropic spatial resolution of <2 µm in tissue. The proposed system could approximately double the ranging depth and extend the DOF using the dual-spectrometer design and the forward-model based digital refocusing method, respectively. We demonstrate that the novel system is capable of visualizing the full thickness of the pig cornea over the ranging depth of 3.5 mm and the border of the corneal endothelial cells 8 times Rayleigh range away from the focal plane. This technology has the potential to realize cellular resolution corneal imaging in vivo.

Highlights

Corneal disease is the second most common cause of blindness or visual impairment worldwide as corneal homeostasis can be perturbed by lots of pathological conditions [1,2]
Imaging the cellular structures of the posterior cornea the endothelial cells is critical for the evaluation of the corneal grafts during corneal transplantation and diagnosis of corneal diseases
Current anterior segment optical coherence tomography (OCT) has been established as a clinical gold standard, it is not capable of providing cellular information

Summary

Introduction

Corneal disease is the second most common cause of blindness or visual impairment worldwide as corneal homeostasis can be perturbed by lots of pathological conditions [1,2]. A large scanning area of the cornea is necessary because it can potentially provide an improvement in the precise location of corneal lesions and planning of medical and surgical treatment [7] Current imaging techniques such as confocal microscopy [8,9] and high-frequency ultrasound have limitations, such as a narrow field of view or limited resolution respectively [10]. The requirements of large scanning imaging area, high axial resolution and high lateral resolution with extended DOF are necessary to provide a possibility to improve diagnostics and visualization of eye corneas. The endothelial cell borders even at the out-of-focus regions can be visualized thanks to this method

Experimental setup

Corneal imaging

Findings

Discussion and conclusion