Wave aberration of the mouse eye

Abstract

Purpose: The wavefront sensor spots upon which aberration measurements depend have poor quality in mice 1,2 due to light reflected from multiple retinal layers. We have designed a wavefront sensor that favors light from a specific retinal layer to establish what benefits adaptive optics (AO) might bring to retinal imaging in the living mouse eye.

Methods: The wavefront sensor used a large diameter beacon to decrease the depth of focus. The beacon was focused on outer retina. Using reflected light (794 nm), we measured aberrations up to 10th order (321 lenslets filling a 2 mm dilated pupil) in 20 eyes from 10 C57BL/6J mice between 75 and 150 days of age.

Results: This method produces wavefront sensor spots with improved quality. By discriminating light from different retinal layers, we show that mice are myopic, not hyperopic as is frequently reported. The higher order aberrations are smaller than those of the human eye for the same numerical aperture. A mouse adaptive optics camera would need to correct Zernike orders up to and including at least 6th order to achieve diffraction-limited imaging (Strehl ratio > 0.8). Without AO, with only defocus and astigmatism corrected, a 0.8 mm pupil size will yield the best image quality on average.

Conclusions: This wavefront sensor design improves measurements in the mouse. The optical quality of the mouse eye is remarkably good, better for retinal imaging than the human eye. AO can provide additional improvements in retinal image quality and will allow monitoring of disease progression and the efficacy of therapy in single animals over time.

Acknowledgments

NIH Grant EY 001319, EY014375; NSF STC grant No. AST-9876783; Research to Prevent Blindness. We thank Wanli Chi, Robin Sharma, Jason Porter, Marsha Kisilak, RamKumar Sabesan, Lu Yin, Jennifer Hunter, Alf Dubra, Ben Masella, Boshen Gao and Nicole Putnam for their help on this work.