Imaging retina in rodent eyes with high resolution polarization sensitive optical coherence tomography

Abstract

 

Purpose

 

Animal models play an important role in studies of ocular diseases such as age-related macular degeneration and glaucoma. The purpose of this study is to develop high-resolution polarization sensitive OCT (HR-PS-OCT) for imaging the eyes of rodents and to demonstrate in vivo imaging in rats and mice.

 

Methods

 

Spectral domain HR-PS-OCT with an axial resolution of 5.1 µm in air (3.8 µm in tissue) was developed. The central wavelength of the used light source (superluminescent diode) was 840 nm, acquisition speed was 83 kHz. Due to the high scan speed, a whole 3D data set can be acquired in few seconds (1024x200x1536 in 3.44 s) which reduces motion artifacts. In addition to standard OCT images that show sample reflectivity, phase retardation and fast axis orientation images were calculated. PS-OCT images enable the identification of birefringent tissues (such as sclera) and depolarizing tissues (such as retinal pigment epithelium - RPE, choroid).

 

Results

 

Healthy non-pigmented/pigmented rats as well as pigmented mice were imaged with the system. On the high-resolution reflectivity images, all retinal layers were observed in all animals. On the phase retardation images, the birefringent properties of the sclera and depolarization properties of the RPE-choroid were observed.

 

Conclusions

 

A dedicated HR-PS-OCT system for ocular imaging in rodents was developed and was demonstrated in vivo on rats and mice. On the high-resolution images all retinal layers could be identified. From polarization sensitive images birefringent and depolarizing tissues were identified. OCT represents a non-lethal and non-invasive alternative to histology. Our results demonstrate the feasibility of the system for high speed and high-resolution imaging of the rodent retina in longitudinal studies.