Angle Kappa Influence on Multifocal IOL Outcomes

Abstract

Purpose: To characterize angle kappa and study the relationship between preoperative angle kappa and postoperative refractive accuracy, visual outcomes, and patient satisfaction in a large population of eyes with multifocal intraocular lens (MIOL) implantation. Methods: A comprehensive electronic medical record chart review of 26,470 consecutive eyes that underwent immediate sequential bilateral cataract or refractive lens exchange with MIOLs was conducted. The primary outcome measures were postoperative monocular uncorrected distance visual acuity (UDVA), manifest refraction sphere and cylinder, spherical equivalent (SEQ), defocus equivalent (DEQ), subjective quality of vision at near, intermediate, and distance, and the likelihood of recommending the procedure. Relationships between preoperative angle kappa and postoperative outcomes were assessed with Pearson correlations. Results: Angle kappa followed a right-skewed normal distribution ( R 2 = 0.99) with a mean ± standard deviation of 0.64 ± 0.27 mm. No clinically meaningful relationship was found between preoperative angle kappa and postoperative sphere, cylinder, SEQ, and DEQ, all with R 2 ⩽ 0.0005. Similarly, there was no clinically meaningful relationship between preoperative angle kappa and postoperative UDVA ( R 2 = 0.001), postoperative satisfaction for near, intermediate, and distance vision (all R 2 ⩽ 0.0023), or for recommending the MIOL surgery to friends and relatives ( R 2 = 0.0000). Conclusions: Preoperative angle kappa does not have a predictive clinical impact on postoperative MIOL visual outcomes, refractive accuracy, or subjective patient satisfaction. Angle kappa as a single variable cannot be used to determine MIOL candidacy. [ J Refract Surg . 2023;39(12):840–849.]

Comment on: “Angle Kappa is Not Correlated with Patient-Reported Outcomes After Multifocal Lens Implantation” [Letter]

“…We demonstrated that preoperative angle kappa did not have a predictive clinical impact on postoperative MIOL visual outcomes, refractive accuracy, subjective patient satisfaction at near, intermediate and far distance, nor with the likelihood of recommending an MIOL procedure to friends and relatives. 2 Our study also noted a larger angle kappa in right vs. left eyes. Liu et al add validity to our existing findings 2 and confirms, along with several previous studies, 3–9 that angle kappa as a single variable cannot be used to determine MIOL candidacy.…”

“… 2 Our study also noted a larger angle kappa in right vs. left eyes. Liu et al add validity to our existing findings 2 and confirms, along with several previous studies, 3–9 that angle kappa as a single variable cannot be used to determine MIOL candidacy. The novelty of the study by Liu et al lies in reaching the same conclusion with angle kappa measurements taken by Pentacam and adding photic phenomena data.…”

“…This study examines MIOL patient-reported outcomes in relation to preoperative angle kappa in a cohort of 26,470 eyes. 2 We appreciate the authors for reproducing and validating our findings by utilizing the Pentacam "chord length" instead of the Orbscan kappa displacement distance to measure angle kappa. Their study, mirroring our conclusions, confirms that angle kappa lacks significant correlation with patient-reported outcomes and cannot be used as a criterion for MIOL candidacy.…”

“…This study examines MIOL patient-reported outcomes in relation to preoperative angle kappa in a cohort of 26,470 eyes. 2 …”