Visual acuity and blur: An extended depth-of-focus model

Area of Science:

• Ophthalmology
• Optical Engineering
• Visual Science

Background:

• Understanding visual acuity requires accounting for optical aberrations.
• Defocus curves are crucial for assessing visual performance.
• Higher-order aberrations (HOA) significantly impact visual quality.

Purpose of the Study:

• To propose a simple model for the quantitative relationship between visual acuity and defocus.
• To incorporate the effects of higher-order aberrations (HOA) into existing blur models.
• To develop a model applicable to defocus curves.

Main Methods:

• Extended Blendowske's basis model for visual acuity and blur.
• Transformed aberrometric refractive errors into a single blur quantity (dioptric distance).
• Did not include the influence of asymmetric aberration axes or pupil size.

Main Results:

• Generated reference data for a bi-aspheric multifocal correction profile for presbyopia.
• The model's reference data align with existing literature for the specified profile.
• The extended model provides a valid description for defocus curves.

Conclusions:

• The model can determine depth-of-focus effects in the presence of HOA.
• Experimental data uncertainties, particularly pupil diameter, limit model refinement.
• Theoretical arguments support the validity of the extended model for defocus curves.