Spherical lens versus aspheric artificial cornea for intraocular lens testing

Area of Science:

• Ophthalmic optics
• Biomedical engineering
• Optical testing

Background:

• Current International Organization for Standardization (ISO) model eyes use artificial corneas with spherical aberration matching human corneas.
• Aspheric lenses, while effective, are costly and challenging to manufacture for use as artificial corneas.

Purpose of the Study:

• To demonstrate the feasibility of replacing aspheric artificial corneas with simpler spherical lenses in the ISO model eye.
• To propose a modified ISO model eye for intraocular lens (IOL) testing using a spherical artificial cornea.

Main Methods:

• Investigated the use of a biconvex spherical lens as an alternative to aspheric artificial corneas.
• Established a linear relationship between the Coddington shape factor and induced spherical aberration for spherical lenses.
• Matched the wavefront error of the spherical lens to that of the aspheric lens.

Main Results:

• A simple biconvex spherical lens can effectively replace an aspheric lens in the ISO model eye.
• The induced spherical aberration of a spherical lens can be controlled by its Coddington shape factor.
• A modified ISO model eye with a spherical artificial cornea can achieve similar wavefront error to one with an aspheric cornea.

Conclusions:

• A spherical lens offers a cost-effective and manufacturable alternative to aspheric lenses for artificial corneas in the ISO model eye.
• The proposed modified ISO model eye is suitable for on-axis optical assessment of intraocular lenses.
• Further discussion is needed regarding the suitability of this modification for off-axis testing.