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Development and application of a new formula to increase the safety and predictability of vault lens separation for the Implantable Collamer Lens (ICL) using Artemis Insight 100 VHF digital ultrasound biometry

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First Author: D.Reinstein UK

Co Author(s):    R. Vida   T. Archer   v -   -. -           

Abstract Details

Purpose:

To develop a new model to predict vault lens separation 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.

Setting:

London Vision Clinic, London, UK

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 lens separation 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 ciliary body inner diameter proved to be so much more significant than STS that STS no longer entered into the model. The new model also found scotopic pupil size to be a significant predictor, which has to date not been a part of any previously published model. This is also the first study publishing a plot of attempted vs achieved vault outcomes. Using this model we expect the probability of a significant outlier requiring exchange to go well below 1%. Testing this will be the subject of future study.

Financial Disclosure:

... gains financially from product or procedure presented