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.

PURPOSE: To evaluate the predictive value of the preoperative orientation and offset of angle alpha(chord alpha) and angle kappa(chord mu) for visual outcomes in patients who underwent trifocal intraocular lens (IOL) implantation.

METHODS: Patient records of eyes that underwent AT LISA tri 839MP implantation were retrospectively collected and grouped according to the preoperative offset and orientations of chord alpha and chord mu. The two-dimensional location of each angle was described by the interaction of the orientation and offset. Multiple regression models and likelihood ratio tests were established to determine their predictive value for postoperative visual outcomes, National Eye Institute Visual Function Questionnaire (NEI-VFQ) and Quality of Vision Questionnaire (QoV) scores.

RESULTS: One hundred and two patients (184 eyes) were included. The orientation of chord alpha had a significant overall prediction to postoperative visual outcomes (p = 0.014). A superior chord alpha was an independent predictor of better postoperative uncorrected distance visual acuity (UDVA, p < 0.001) and a larger modulation transfer function (MTF) curve average height (p = 0.041). However, the offsets of chords alpha and chord mu and the orientation of chord mu did not significantly predict UDVA, uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), MTF, total ocular aberration (TOA), or high-order aberration (HOA).Better patient reported general vision was correlated with a nasal chord alpha (p = 0.012), whereas better near vision was correlated with a smaller kappa offset (p = 0.022) and nasal chord alpha (p = 0.019). The absence of postoperative halos was independently associated with the location of nasal chord alpha(p = 0.039), while starbursts were independently correlated with a larger chord mu offset (p = 0.007).

CONCLUSION: A superior chord alpha was an independent predictor of better postoperative visual outcomes after trifocal IOL implantation. The predictive value of either the orientation or offset of chord mu for the VA, TOA and HOA was insignificant.

TRIAL REGISTRATION: Not applicable.

KEY MESSAGES: 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.