Full ocular biometry through dual-depth whole-eye optical coherence tomography.

Hyung-Jin Kim,Minji Kim,Beop-Min Kim,Youngwoon Choi,Min Gyu Hyeon

doi:10.1364/boe.9.000360

Abstract

We propose a new method of determining the optical axis (OA), pupillary axis (PA), and visual axis (VA) of the human eye by using dual-depth whole-eye optical coherence tomography (OCT). These axes, as well as the angles "α" between the OA and VA and "κ" between PA and VA, are important in many ophthalmologic applications, especially in refractive surgery. Whole-eye images are reconstructed based on simultaneously acquired images of the anterior segment and retina. The light from a light source is split into two orthogonal polarization components for imaging the anterior segment and retina, respectively. The OA and PA are identified based on their geometric definitions by using the anterior segment image only, while the VA is detected through accurate correlation between the two images. The feasibility of our approach was tested using a model eye and human subjects.

Highlights

The human eye is an optical system composed of a cornea, an iris, a crystalline lens, and a retina
The optical components of the human eye are aligned along the optical axis (OA); the human views objects along the visual axis (VA), which is tilted at an angle of approximately 5° with respect to the OA [2]
We developed a new method of determining the OA, pupillary axis (PA), VA, and values of α and κ using a whole-eye optical coherence tomography (OCT) system

Summary

Introduction

The human eye is an optical system composed of a cornea, an iris, a crystalline lens, and a retina. A frequency shifter (FS; Brimrose Corp., USA) was employed to extend the imaging depth and enable imaging of the entire anterior segment from the top surface of the cornea to the posterior surface of the crystalline lens [18]. It shifted the frequency of the reference light for the anterior segment to 300 MHz. Highspeed balanced photodiode detectors (BPDs 1 and 2; Thorlabs, USA) were used to detect the interference signals.

Image-distortion correction

Results

Findings

Discussion