Abstract
Purpose: :
We have measured the wave aberration of the mouse eye to establish the requirements for an adaptive optics camera that could achieve diffraction-limited retinal imaging. Garcia de la Cera et al. [1] reported aberration measurements up to 4th order on 12 mouse eyes. We extend these data by measuring a larger number of aberrations across a larger, fully dilated pupil.
Methods: :
Using a Shack-Hartmann wavefront sensor operating in reflected light (794 nm), we measured aberrations up to 10th order with 321 lenslets filling a 2 mm, dilated pupil. C57BL/6J pigmented (n=5) and albino mice (n=2) between 75 and 150 days of age were used. Each was anesthetized and aligned so that the first Purkinje image of a source on the optical axis of the instrument was centered in the mouse’s pupil. Speckle was reduced by scanning the beam across the retina. Eyes were periodically lubricated to avoid corneal dehydration.
Results: :
As reported by Biss et al. [2] and Garcia de la Cera et al. [1], wavefront sensor spot quality was poor in mice compared with primates. Pigmented mice had better spot quality than albino mice. Nonetheless, we obtained repeatable wave aberration measurements. At the same numerical aperture, the higher order aberrations of the mouse eye are smaller than those of the human eye. Moreover, the numerical aperture of the mouse eye can be twice as large as that of the human, making it theoretically possible to achieve a resolution of 0.7 um at 550 nm, two times better than can be achieved in human. An adaptive optics camera for the mouse would need to measure and correct Zernike orders up to and including at least 6th order to achieve diffraction-limited imaging (Strehl ratio > 0.8).
Conclusions: :
The ability to capture the entire wave aberration in the mouse eye over a fully dilated pupil with reflected light is promising for high-speed adaptive correction of mouse retinal images. Such an instrument could allow microscopic imaging of retinal development, disease progression, or the efficacy of therapy in single animals over time.
References: :
[1] Garcia de la Cera E, Rodriguez G, Llorente L, Schaeffel F, Marcos S. Optical aberrations in the mouse eye. Vision Res. 2006;46:2546-2553.[2] Biss DP, Sumorok D, Burns SA, et al. In vivo fluorescent imaging of the mouse retina using adaptive optics. Opt Lett. 2007;32:659-661.
Keywords: aberrations • optical properties • imaging/image analysis: non-clinical