Alpha and Kappa angle on postoperative visual quality in cataract surgery

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Optics

Background:

• Accurate measurement of ocular angles is crucial for predicting visual outcomes.
• Multifocal intraocular lenses (MIOLs) implantation aims to improve visual quality but can be affected by preoperative ocular parameters.

Purpose of the Study:

• To investigate the influence of preoperative Alpha angle and Kappa angle on postoperative visual quality after MIOLs implantation.
• To establish predictive models for these angles based on patient demographics and ocular measurements.

Main Methods:

• Collected Alpha and Kappa angles using IOL Master 700, iTrace, and Pentacam before and after cataract surgery.
• Assessed postoperative visual quality indicators including high-order aberrations (HOA), modulation transfer function (MTF), and point spread function (PSF).
• Employed multiple linear regression and Pearson correlation analyses to determine relationships between angles and various ocular parameters.

Main Results:

• Developed predictive models for Alpha and Kappa angles based on age, axial length, keratometry, and corneal white-to-white distance.
• Found a weak positive correlation between Alpha and Kappa angles (r=0.291, P=0.000).
• Kappa angle significantly predicted HOA, MTF, and PSF, while Alpha angle did not.

Conclusions:

• Patients with older age, flatter keratometry, and shorter corneal white-to-white distance may have larger Alpha and Kappa angles.
• Kappa angle is a significant predictor of postoperative visual quality and should be carefully considered during MIOLs selection.
• The preoperative standard for Kappa angle may be relaxed based on axial length and keratometry.