Improvements to multi-offset adaptive optics scanning laser ophthalmoscopy for in vivo imaging of individual retinal ganglion cell layer neurons in humans

Retinal ganglion cells (RGCs) are the primary output neurons of the retina. RGC dysfunction and death can cause irreversible vision loss in glaucoma and other ocular diseases. However, no methods exist to evaluate RGCs at the level of single cell in the living human eye in the clinic. Our aim is to implement a technique revealing the retinal ganglion cell layer neurons whose contrast, robustness and acquisition time would make it suitable for clinical diagnosis and monitoring of patients. While previously we were able to demonstrate high contrast imaging in monkeys, here we propose a new adaptive optics scanning laser ophthalmoscope configuration that allows us to achieve similar results on humans in vivo. In particular we used a new detection scheme that allowed us to switch from two light sources to one thereby enabling us to increase the light power, eliminate problems caused by chromatic aberration and improve the image registration process. Here we show that this optimized detection scheme and image processing pipeline improve the multi-offset technique for imaging of human RGC layer neurons.