Non-invasive Quantitative Measurement of Axotomy-induced Retinal Degeneration in Rats Using Fourier Domain Optical Coherence Tomography

Abstract

Purpose: : The purpose of this preliminary study is to investigate Fourier Domain Optical Coherence Tomography (FD OCT) with complementing computational tools for non-invasive quantitative measurement of axotomy-induced retinal degeneration in rats.

Methods: : A prototype spectrometer based FD OCT system was used. Images of the retinas from axotomy and normal rats were acquired non-invasively using FD OCT with the specimen anesthetized. Manual and automated segmentation were used to measure the thickness of the retinal layers and to investigate day to day repeatability and animal to animal variability.

Results: : Volumetric images of the rat retina Fig 1 (a) were acquired, consisting of FD OCT depth profiles Fig 1 (b). The thickness of the combined ganglion cell layer and inner plexiform layer decreased progressively and quantitatively over a period of two weeks in the axotomy rats. The data correlates well with the known progression of RGC loss in ON axotomy.

Conclusions: : FD OCT cannot easily differentiate between GCL and IPL in rat retina. However, the combined thickness can be measured to study quantitative ganglion cell degeneration.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non-clinical