Combining coma with astigmatism can improve retinal image over astigmatism alone

Area of Science:

• Ophthalmology
• Optical Engineering
• Vision Science

Background:

• Retinal image quality is crucial for visual perception.
• Non-rotationally symmetric aberrations like coma and astigmatism can degrade vision.
• Understanding the interplay of these aberrations is key to improving visual outcomes.

Purpose of the Study:

• To investigate whether combinations of coma and astigmatism improve retinal image quality compared to astigmatism alone.
• To quantify the impact of these combined aberrations on visual acuity (VA) and Strehl Ratio.
• To explore the optimal levels of coma for mitigating the effects of astigmatism.

Main Methods:

• Simulations of retinal image quality using Strehl Ratio.
• Adaptive optics measurements of visual acuity under controlled defocus, astigmatism, and coma.
• Systematic variation of astigmatism (0-1.5D) and defocus (-1 to 1D).

Main Results:

• Combinations of coma and astigmatism improved Strehl Ratio by up to 1.7 times compared to astigmatism alone.
• Optimal coma levels were found to be non-zero for all tested astigmatism levels (except 0D).
• Decimal visual acuity improved by 28% and 47% with combined coma and astigmatism versus astigmatism alone in human subjects.

Conclusions:

• Non-rotationally symmetric aberrations, specifically the combination of coma and astigmatism, can beneficially modulate retinal image quality.
• This interaction offers potential for novel vision correction approaches.
• The beneficial effect is diminished in the presence of typical normal levels of higher-order aberrations (HOA).