Abstract
Purpose: :
To develop a confocal adaptive-optics scanning laser ophthalmoscope (AO-SLO) specifically for mouse retinal imaging. In vivo retinal imaging has been shown to be an invaluable tool for visualizing biological processes unfold in real-time. The ability to resolve retinal microstructure in vivo can greatly advance our understanding of retinal microanatomy, normal function and disease. Transgenic mice are frequently used for mouse models of retinal diseases. However, current retinal imaging instruments lack the optical resolution and range of fluorescent channels necessary to visualize retinal detail in mice.
Methods: :
Our AO-SLO is composed of a custom-built video-rate SLO optimized for mouse eye imaging, with three excitation laser wavelengths (491 nm, 532 nm, 638 nm) and three simultaneous detection channels. It comprises a sensor-less AO system (no Shack Hartmann sensor) that corrects wavefront aberrations by optimizing confocal image sharpness using a stochastic parallel gradient descent algorithm to modulate a deformable mirror. Exchangeable telescopes allow the field of view to be adjusted from 11° to 45°and to match the incident laser beam size to the pupil of the eye.
Results: :
It is possible to resolve detailed retinal microstructures, such as the retinal vasculature, the axons and dendrites of ganglion cells, and the processes of retinal microglia. In vivo time-lapse imaging showed that the dendrites of microglia are highly motile and appear to be constantly probing their immediate environment. Similarly, we observe the slow decline of retinal axons in models of neurodegeneration.
Conclusions: :
High-resolution in vivo retinal imaging with an SLO is a valuable tool to show, in real time, the fate of different retinal cell populations under normal and pathological conditions.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: non-clinical • retina