System design considerations to improve isoplanatism for adaptive optics retinal imaging

Area of Science:

• Ophthalmology
• Optical Engineering
• Biomedical Imaging

Background:

• Adaptive optics (AO) retinal imaging is hindered by anisoplanatism, where wavefront aberrations vary across the field of view.
• This limits the area achieving diffraction-limited image quality in a single acquisition.

Purpose of the Study:

• To explore alternative AO modalities inspired by astronomy to mitigate anisoplanatism.
• To investigate system design modifications for improving AO performance across the retinal field of view.

Main Methods:

• Conducted optical design analysis and computer modeling of various AO modalities and schematic eyes.
• Evaluated off-axis performance limitations and the impact of system parameters versus ocular characteristics.
• Modeled modifications to conventional AO systems, including gradient index lenses and mirror-based relay optics with beam deviations.

Main Results:

• Off-axis performance was primarily limited by system parameters, not the eye's inherent optical properties.
• Alternative AO modalities showed limited benefit over conventional AO due to these system limitations.
• Replacing system lenses with gradient index versions and incorporating off-the-plane beam deviations showed promise for reducing anisoplanatism.
• Demonstrated that the optimal position for a single AO corrector is not necessarily in the pupil plane.

Conclusions:

• Conventional AO system design modifications are more effective for reducing anisoplanatism than the explored alternative modalities.
• Gradient index lenses and strategic beam deviations represent promising strategies for enhancing AO retinal imaging.
• The findings challenge the conventional placement of AO correctors, suggesting flexibility for improved performance.