Purpose:

To develop a new model to predict lens vault of the Implantable Collamer Lens (ICL) (STAAR Surgical) using the Artemis Insight 100 very high-frequency (VHF) digital ultrasound (ArcScan Inc) biometry and determine vault predictability achieved.

Methods:

42 consecutive V4c EVO and EVO+ ICL procedures were performed choosing lens size by using sulcus-to-sulcus and lens-rise measurements from VHF digital ultrasound biometry and the published Kojima formula. Stepwise multivariate regression analysis was performed retrospectively to develop a model predicting central vault including the following variables: ICL size, ICL power, sulcus-to-sulcus (STS), ciliary body inner diameter (CBID), zonule-to-zonule, STS lens rise (STSL), ACD, anterior chamber angle, scotopic pupil diameter (SPD), angle-to-angle, and white-to-white. The resulting regression model was used to select lens size for a subsequent 36 consecutive eyes

Results:

Statistically significant variables were ICL size, ICL power, CBID, STSL, and SPD. The primary 42 eyes (mainly using the Kojima formula) achieved a mean vault of 505±194µm, a range of 710µm (150-860µm) and an interquartile (IQ) range of 249µm. Using the new model, the next 36 eyes achieved a normalized mean vault of 579±163µm, a reduced range of 564µm (230-794µm) and a reduced IQ-range of 163µm. In an attempted versus achieved analysis, 56% of eyes were within 100µm and 91% were within 300µm of expected vault.

Conclusions:

The CBID proved to be more significant than STS. The model found scotopic pupil to be a significant predictor, which has not been a part of any previously published model. This is the first study publishing a plot of attempted vs achieved vault outcomes. Using this model we expect the probability of outliers requiring exchange to go well below 1%.