Two-Dimensional Biometry of the Whole Mouse Eye Using Optical Coherence Tomography

Abstract

Purpose: : To demonstrate the feasibility of acquiring quantitative two-dimensional images of the whole mouse eye in vivo using Optical Coherence Tomography (OCT).

Methods: : A time-domain OCT system with 7.4mm axial scan length and 8 micron axial resolution in tissue was coupled with a telecentric beam delivery system providing a 10mm depth of focus with a 0.12 mm spot diameter in air. The system acquires non-contact images of the anesthetized mouse eye in approximately 1 second. The mouse is placed in a custom-designed holder and positioning stage which allow precise centration and alignment of the mouse eye. The control software provides a live display of the image to facilitate positioning and alignment. To ensure consistent alignment with the central meridional plane, multiple cross-sectional images of the eye are acquired and the image with the largest pupil diameter is selected. The system was evaluated on six 2-month old C57BL/6 mice. Images were processed to obtain corneal thickness, lens thickness, vitreous thickness and axial eye length measured from anterior corneal surface to anterior retinal surface.

Results: : Images of the whole eye were acquired successfully in all animals. Cross-sectional images show the entire cornea from limbus to limbus and the entire anterior chamber. The view of the crystalline lens, posterior segment and retina is limited by the pupil diameter. The following biometric data was obtained on 2 month old mice: corneal thickness: 0.120+/-0.006mm, anterior chamber depth: 0.398+/-0.015 mm, lens thickness: 1.770+/-0.044 mm, vitreous depth: 0.586+/-0.037 mm, axial eye length: 3.089+/-0.047 mm, retinal thickness: 0.215+/-0.021 mm. Quantitative measurements of the posterior corneal and lens surface curvatures and of anterior chamber angle require correction of distortions due to refraction.

Conclusions: : The whole-eye OCT measurements are consistent with previously published values obtained by histology or optical or ultrasound biometry. The study demonstrates the feasibility of acquiring reproducible two-dimensional images of the whole mouse eye for precise quantitative biometric studies of mouse eye development.Support: R03-EY016322 (VP); F31EY15395 (DB); F32EY15630 (SRU); NIH center grant P30-EY014801;Henri and Flore Lesieur Foundation (JMP). Unrestricted grant to Bascom Palmer Eye Institute from Research to Prevent Blindness.

Keywords: anatomy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • development