Independent factors associated with ICL haptic position: a multivariate analysis of anterior and posterior segment parameters

PURPOSE: To analyze anterior segment anatomy in relation to the ICL haptic position, and identify independently associated factors using multivariate analysis. METHODS: One month after ICL implantation, ultrasound biomicroscopy (UBM) was used to observe the position of the ICL haptics. Patients were classified into three groups based on haptic position: ciliary sulcus, ciliary body, and under the ciliary body. Preoperative ocular structural parameters were collected. One-way ANOVA was used to compare the parameters among the three groups, and multivariate multinomial logistic regression was performed to identify factors independently associated with haptic position. RESULTS: The numbers of patients (eyes) with haptics in the ciliary sulcus, ciliary body, and under the ciliary body were 34 (47 eyes), 26 (42 eyes), and 20 (38 eyes), respectively. Univariate analysis showed significant differences in vault, white-to-white distance (WTW), anterior chamber depth (ACD), spherical equivalent (SE), anterior chamber volume (ACV), lens thickness(LT), crystalline lens rise (CLR), maximum ciliary body thickness (CBTmax), trabecular-ciliary angle (TCA), and iris-ciliary process distance (ICPD) among the three groups (all P < 0.05). Multivariate multinomial logistic regression revealed that age (OR per 5 years = 1.21, 95% CI 1.06-1.39, P = 0.006), SE (OR per 1 D = 1.84, 95% CI 1.24-2.74, P = 0.003), and ICL size (OR per 1 mm = 0.022, 95% CI 0.002-0.279, P = 0.003) were independently associated with ciliary sulcus haptic placement compared with under the ciliary body placement. CONCLUSIONS: The position of ICL haptics strongly correlates with vault. Haptic position is independently associated with age, SE, and ICL size. The apparent associations of ACV and ciliary body morphology with haptic position, as observed in univariate analyses, may be due to confounding factors such as age.