Simulation of Corneal imaging properties for near objects.

Area of Science:

• Ophthalmic optics
• Biomedical engineering
• Computational vision science

Background:

• Understanding corneal imaging properties is vital for accurate vision correction.
• Schematic model eyes are essential tools for simulating ocular optics.
• Corneal aberrations can significantly impact visual quality, particularly at different object distances.

Purpose of the Study:

• To investigate the impact of aperture size and object distance on corneal imaging metrics using raytracing simulation.
• To analyze how spherical aberration and focus change with varying conditions in different schematic eye models.

Main Methods:

• Raytracing simulations were performed on four schematic model eyes (Liou-Brennan, Atchison, Gullstrand, Navarro).
• Simulations covered four aperture sizes (2-5 mm) and 30 object distances (10 cm to infinity).
• Wavefront analysis using Zernike components identified spherical aberration and focus variations.

Main Results:

• Focal distance increased from ~31 mm (infinity) to ~40 mm (10 cm).
• Best focus shifted closer to the cornea than paraxial focus, with larger overestimation at smaller distances and larger apertures.
• Spherical aberration increased significantly at closer object distances, varying across model eyes.

Conclusions:

• Corneal imaging properties, particularly spherical aberration, are highly sensitive to object distance, especially for near vision.
• These findings necessitate consideration for designing advanced lenses like multifocal or extended depth-of-focus lenses.
• Accurate modeling of corneal optics is crucial for optimizing visual performance across various viewing conditions.