Long Stroke Wavefront Correctors for Retinal Imaging

DESCRIPTION (provided by applicant): This proposal describes a plan to develop long stroke MEMS deformable mirrors suitable for use in commercial ophthalmic adaptive optics. They will be designed to permit diffraction-limited retinal imaging through dilated pupils in at least 90% of the human population. Electrostatic actuator design and manufacturing processes demonstrated in Phase I research will be used as a foundation for these MEMS-DMs, which will be produced using silicon wafer batch-manufacturing. Based on prior research, it is estimated compensation of aberrations of the eye will require up to 12fm of wavefront compensation (with focus and astigmatism compensated before MEMS-DM correction). Because mirror deformation is doubled in the wavefront by reflection, this will require a DM with at least 6fm of stroke at each actuator. A second goal will be to demonstrate diffraction-limited retinal imaging in human subjects possessing optical aberrations of the eye that encompasses more than 90% of the range found in the population. The long-stroke MEMS deformable mirror will be combined with the optical doubler demonstrated in the Phase I effort to achieve an effective deformable mirror motion of 12fm, corresponding to 24fm of wavefront correction, and will be integrated into a proven adaptive optics scanning laser ophthalmoscope design. Adding the optical doubler to the system will allow for the deformable mirror to correct for low order (astigmatic) aberrations. This large stroke, combined with a Badal optometer design, will eliminate the need to use corrective lenses for each subject eye and allow unprecedented in vivo imaging of the human retina. Researchers and clinicians have been unable to see critical features in the human retina due to ocular aberrations that limited imaging resolution. A successful completion of the proposed project will provide the enabling component for better resolution imaging of the human retina than ever before. This improvement in image quality will allow clinicians to detect and diagnose diabetic retinopathy and macular degeneration as well as to determine the efficacy of drugs in drug studies.