Basic Optics Underlying Current Intraocular Lenses.

Area of Science:

• Ophthalmology
• Optical Engineering
• Optometry

Background:

• Multifocal intraocular lenses (IOLs) are increasingly used for cataract and presbyopia correction.
• Clinicians require a strong understanding of IOL optics for optimal patient selection.
• Existing reviews often lack clinical applicability for surgeons.

Purpose of the Study:

• To systematically review fundamental optical concepts relevant to multifocal IOLs.
• To explain the mechanisms of various multifocal IOL technologies.
• To bridge the gap between optical principles and clinical practice in IOL selection.

Main Methods:

• Review of fundamental optics: properties of light, geometric optics, Gaussian approximation.
• Analysis of lens performance metrics: point spread function, modulation transfer function (MTF).
• Explanation of optical aberrations: spherical and chromatic aberrations and their clinical implications.

Main Results:

• Refractive extended depth of focus (EDOF) lenses control higher-order spherical aberrations.
• Diffractive lenses use kinoforms to create multiple foci and correct chromatic aberration.
• Multifocality leads to optical compromises, including reduced MTF and potential photic phenomena (glare, halo).

Conclusions:

• Multifocal IOLs improve quality of life by reducing spectacle dependence.
• Image quality is often compromised compared to monofocal IOLs.
• Ophthalmologists must understand IOL optics to select appropriate lenses and manage outcomes.