Refractive adaptive optics scanning light ophthalmoscope with fast 2D MEMS scanner

Area of Science:

• Ophthalmic imaging
• Optical engineering
• Biomedical optics

Background:

• Small animal models are crucial for studying ocular diseases.
• High-resolution in vivo imaging of the rodent retina is challenging due to small pupils and dynamic eye movements.

Purpose of the Study:

• To design and validate a refractive adaptive optics scanning light ophthalmoscope for small animal retinal imaging.
• To achieve diffraction-limited imaging performance through a small 1.8 mm pupil.
• To enhance imaging speed and stability for improved visualization.

Main Methods:

• Developed a novel optical setup using modified afocal relays and achromatic doublets.
• Employed real ray tracing to compare wavefront correction methods for focus errors.
• Integrated a 2-dimensional optical scanner with high resonant frequency and low distortion.
• Utilized polarization control, focal length selection, and lens tilting to minimize reflections.
• Implemented scanner orientation and trigger signals for image correction.

Main Results:

• Achieved diffraction-limited imaging in pupil and retina conjugates.
• Demonstrated effective correction of large focus errors using different wavefront correction strategies.
• Enabled a doubled frame rate compared to previous instruments.
• Successfully imaged mouse retinas using confocal and non-confocal reflectance modalities at 800 nm.

Conclusions:

• The developed adaptive optics ophthalmoscope provides high-resolution retinal imaging in small animals.
• The instrument's design offers improved speed, stability, and optical performance.
• This technology advances the capability for in vivo study of rodent ocular physiology and pathology.