Adaptive optics in the mouse eye: wavefront sensing based vs image-guided aberration correction

Abstract

Adaptive Optics (AO) is required to achieve diffraction limited resolution in many real-life imaging applications in biology and medicine. AO is essential to guarantee high fidelity visualization of cellular structures for retinal imaging by correcting ocular aberrations. Aberration correction for mouse retinal imaging by direct wavefront measurement has been demonstrated with great success. However, for mouse eyes, the performance of the wavefront sensor (WFS) based AO can be limited by several factors including non-common path errors, wavefront reconstruction errors, and an ill-defined reference plane. Image-based AO can avoid these issues at the cost of algorithmic execution time. Furthermore, image-based approaches can provide improvements to compactness, accessibility, and even the performance of AO systems. Here, we demonstrate the ability of image-based AO to provide comparable aberration correction and image resolution to the conventional Shack-Hartmann WFS-based AO approach. The residual wavefront error of the mouse eye was monitored during a wavefront sensorless optimization to allow comparison with classical AO. This also allowed us to improve the performance of our AO system for small animal retinal imaging.

Retinal microvascular and neuronal pathologies probedin vivoby adaptive optical two-photon fluorescence microscopy

“…S6 ) without notable differences in severity across strains. While consistent with most previously reported values 21,25 , our study differs significantly from a recent AO-2PFM study that reported extremely large aberrations (e.g., 12-25 µm P-V 26 ) and found it difficult to resolve microvasculature and cell bodies in 2D in vivo without AO. In contrast, with our carefully designed microscope and system aberration correction procedure, we achieved capillary visualization, 2D single-cell resolution, and retinal layer differentiation by only correcting system aberrations (‘No AO’ in our case).…”

“…Therefore, in vivo characterization of retinal vasculature, especially at the microvasculature level, is of great physiological and clinical importance. Utilizing either confocal microscopy 20,25 or 2PFM 26,40,41 , previous publications have achieved in vivo visualization of retinal microvasculature through either full correction of the mouse eye aberrations 20,25,26 , partial correction of the anterior optics of the mouse eye 41 , or stringent selection of imaging lenses 40 . These prior demonstration-of-principle experiments suggest that in order to image retinal microvasculature in vivo , mouse eye aberrations need to be corrected, either fully or partially.…”

“…It has also been combined with ophthalmological imaging modalities to restore diffraction-limited imaging performance for the human retina 17,18 . Because of the severe aberrations of the mouse eye, AO has also been applied to in vivo imaging of the mouse retina [19][20][21][22][23][24][25][26] . However, there are disagreements in the reported spatial resolutions [19][20][21][22][23][24][25][26] , characteristics and magnitude of aberration [19][20][21][24][25][26] , and the effectiveness of AO 20,21,[24][25][26] .…”

Measurement of Diurnal Variation in Rod Outer Segment Length In Vivo in Mice With the OCT Optoretinogram

“…Although the conclusions from the present investigation rests on results from populations of rods, it should be possible to extend the work to individual rods because investigations with AO-SLO has been able to resolve light reflected from individual mouse rods. 52 , 75 , 76 Ongoing efforts combining AO-OCT, AO-SLO system, 77 , 78 and/or speckle averaging OCT 79 – 81 in mouse photoreceptor imaging also show promise in distinguishing cone backscatter signals from those of the rods in the mouse photoreceptor mosaic. More generally, the approach used here, combined with AO-OCT and AO-SLO should afford efficient use of the ORG in mouse to screen for, and characterize molecular mechanisms that govern rod and cone disc shedding and renewal, 29 , 82 , 83 as well as the mechanisms underlying bleaching-induced outer segments swelling and scattering changes in the posterior eye.…”

Adaptive optics: principles and applications in ophthalmology

“…With an average measured transverse resolution of 1.84μm, images of microscopic structures in the rat retina were captured (127). proposed to measure and correct for aberrations without the need for wavefront sensor (131).…”