The predictive value of the orientation and offset of angle α and angle κ for visual outcomes after trifocal intraocular lens implantation in an Asian cohort

What is known The chord alpha (angle alpha) was found to be predominantly located in the temporal quadrant of the cornea, followed by the superior, nasal, and inferior quadrants. The chord mu (angle kappa) was more evenly distributed in the four quadrants, with 46.2% (85/184) in the temporal quadrant, followed by the inferior, superior, and nasal quadrants. What this paper adds A superior chord alpha orientation was an independent predictor of better postoperative uncorrected distance visual acuity (UDVA) and modulation transfer function average height (MTF AH). However, the interaction of orientation and offset had no predictive value. The orientation and offset of chord mu had no significant predictive value for UDVA, uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), MTF AH, total (TOA), or high-order aberration (HOA). The nasal chord alpha was independently correlated with better patient reported general vision, near vision and absence of halo. A smaller kappa offset was independently correlated with better performance in patient reported near vision and fewer starbursts.