Dual-Plane Shack-Hartmann Wavefront Sensing in a Computer Eye Model Implanted With Rotationally Asymmetric Bifocal...

Area of Science:

• Ophthalmology
• Optical Engineering
• Biomedical Optics

Background:

• Rotationally asymmetric refractive bifocal intraocular lenses (IOLs) present challenges in accurately assessing postoperative visual quality.
• Traditional wavefront sensing methods can produce artifacts when analyzing IOLs with complex optical designs.

Purpose of the Study:

• To evaluate wavefront aberrations in eyes implanted with rotationally asymmetric refractive bifocal intraocular lenses (IOLs).
• To assess the efficacy of a modified Shack-Hartmann wavefront sensor (SHWS) in mitigating artifactual coma during IOL analysis.

Main Methods:

• A simulation study using a computer eye model with a bifocal phase map (3.00 D near addition, 50% energy distribution).
• Wavefront analysis was performed using both a standard integration method and a proposed method combining data from near and far foci.
• The proposed method captures SHWS data at distinct foci and integrates in-focus lenslet images specific to the bifocal IOL zones.

Main Results:

• The standard integration method produced significant artifactual coma (0.57 µm RMS) without ocular aberrations.
• The proposed method reduced residual RMS error to 0.01 µm in the absence of aberrations.
• With ocular aberrations up to the fourth order, the proposed method achieved a mean residual RMS of 35 nm, enabling diffraction-limited sensing.

Conclusions:

• The proposed SHWS integration method effectively overcomes the phase asymmetry inherent in segmented bifocal IOLs.
• This approach provides precise postoperative wavefront data and through-focus visual quality metrics.
• It serves as a robust tool for the clinical evaluation of patients with bifocal IOLs.