RELATIONSHIP OF ANGLE KAPPA TO OCULAR PARAMETERS USING SWEPT-SOURCE OCULAR COHERENCE TOMOGRAPHY IN CATARACT SURGERY PATIENTS

Angle Kappa (Chord mu) can have significant impact on the optical quality and visual performance of toric and multifocal intraocular lenses. The aim of this study was to assess the relationship between angle kappa (chord mu) and ocular parameters in patients attending cataract assessment clinics.

Sussex Eye Hospital, University Hospitals NHS Foundation Trust, Brighton, United Kingdom

This is an observational study of consecuitive patients attending cataract surgery clinic at the Sussex Eye Hospital, Brighton between October 2022 and October 2023. The data on chord mu, age, axial length (AL), anterior chamber depth (ACD), anterior and posterior mean keratometry (Km), mean total keratometry (TK), white-to-white (WTW), central corneal thickness (CCT) and lens thickness (LT) were collected for all these patients. Patients with any warnings on the measurements were excluded. Correlation (Pearsons) between Chord mu and rest of the ocular parameters was calculated. A stepwise backward multiple regression analysis was performed to identify combination of ocular parameters strongly correlating to Chord mu.

2464 eyes (1232 patients) were included in this study. The mean age was 72.7 ±  12.7years (18 to 97 years). Univariate analysis showed a significant positive correlation of Chord mu to age (R=0.55, P=0.01), LT (R=0.16, P<0.01), mean TK (R=0.08, P<0.01) and Km (R=0.08, P<0.01). Whereas there was a significant negative correlation with WTW (R= -0.04, P=0.03), AL (R= -0.19, P<0.01) and ACD (R= -0.2, P<0.01). Male gender (R= -0.04, P=0.05) and CCT (R=0.04, P=0.06) were not significantly correlated. Multivariate step-wise backward regression analysis showed a combination of 4 factors (female sex, reduced AL and ACD and steep Km) to be significantly related to chord mu (angle Kappa).

A combination of factors such as female gender, reduced axial length and anterior chamber depth and higher mean keratometry are correlated to chord mu (angle kappa) in routine patients attending cataract assessment clinics. These findings can be helpful in identification of vulnerable patients who can have appropriate counselling on prognosis of post operative optical and visual outcomes.