Axial Length Acquisition Rates Of The Argos-Biometer And The Iol-Master 700-Biometer In Eyes With Dense Cataracts

To compare  acquisition rates of the axial length measurement in eyes with dense cataracts of two swept source (SS)-Biometers, the ARGOS-Biometer with Enhanced Retinal Visualization (ERV)-mode (Movu/Alcon) and the IOL-Master 700 (Zeiss). The ERV-mode is an optional acquisition mode for the posterior segment. It augments the detection of the retina by shifting the focus of the SS-OCT signal towards the posterior part of the eye similar to the EDI-OCT technology of Spectral Domain OCT devices.

Department of ophthalmology, GLG-Klinikum Barnim, Werner Forßmann Krankenhaus, teaching hospital of the Charité Medical School, Rudolf-Breitscheid-Straße 100, 16225 Eberswalde, Germany. The study was revised by the institutional ethic committee of the Brandenburg Chamber of Physicians. Prospective, randomized, controlled, interventional, single center study.

50 otherwise healthy eyes with very dense cataract according to the clinical LOC-scale III grading (LOCS-III ≥N06, NC6, C5 or P5) will be included in the study. Nuclear density will be objectively measured using the Pentacam PNS-value (Oculus). In randomized order a complete biometric measurement will be attempted with both biometers. If successful, the IOL-selection will be based on the BU2-formula of IOL-Master 700, otherwise on the axial length of the Argos or ultrasound A-scans (Ellex). The axial length acquisition rates will be noted. 6 weeks after surgery, the refractive results will be compared with the calculated values of both biometers. The minimum sample size of 40 eyes was computed for McNemar’s test for correlated proportions.

The primary endpoint of the study is the axial length acquisition rate. Secondary endpoints are Accuracy of lens calculation (refractive error), the comparison of the measurements of the axial length and its measured segments, the mean PNS value and the distribution of the LOCS III-gradings. Exploratory Endpoints are the localization of lens opacification and PNS-values causing the failure of the axial length measurements and other causes complicating the acquisition axial lengths measurements, e.g. lack of fixation. As the study is still ongoing, results are pending but will be expected for report at the ESCRS congress 2022.

SS-OCT biometers have significantly improved axial length acquisition. The ERV- technology of the Argos Biometer adds further amendment in eyes with very dense cataracts. However, as the study is still ongoing only preliminary observations can be made at this time.

This study was supported by an investigator-initiated study grant from Alcon (IIT #65011581)