Retinal image quality for multifocal lenses with on- and off-axis annular zones

Area of Science:

• Ophthalmic Optics
• Visual Science
• Optical Engineering

Background:

• Multifocal intraocular and contact lenses aim to improve depth of focus.
• Conventional designs use annular zones with additional refractive power, creating specific wavefront patterns.

Purpose of the Study:

• To investigate an alternative method for influencing depth of focus in multifocal lenses.
• To compare the effects of wavefront curvature (refractive power) and wavefront tilt on retinal image quality.

Main Methods:

• Calculated retinal image light distributions for a single annulus bifocal lens using diffraction theory.
• Analyzed through-focus scans using four distinct measures of retinal image quality.
• Considered the operational characteristics of Shack-Hartmann wavefront sensors for lens testing.

Main Results:

• Both plus power additions and wavefront tilts were found to be nearly interchangeable in their effect on depth of focus.
• Wavefront tilt offers a viable alternative to traditional refractive power adjustments for modulating focal depth.

Conclusions:

• Altering wavefront tilt, in addition to refractive power, provides a flexible approach to designing multifocal ophthalmic lenses.
• Accurate characterization of lens testing equipment, such as Shack-Hartmann devices, is crucial for reliable analysis.