Biometry Calculation Changes Following Goldmann Applanation Tonometry

Published 2024 - 42nd Congress of the ESCRS

Reference: PP05.17 | Type: Free paper | DOI: 10.82333/frwd-d145

Authors: Karl Mercieca ¹ , Alexandra Rohleder* ¹ , Anja Weschke ¹ , Constance Weber ¹ , Frank Holz ¹

¹University of Bonn,Bonn,Germany

Purpose

To demonstrate the effect of Goldmann Applanation Tonometry (GAT) on Biometry measurements.

Setting

This is an ongoing prospective case series of patients in a glaucoma clinic setting who are subsequently planned for cataract surgery (phacoemulsifcation), with or without minimally invasive glaucoma surgery (MIGS).

Methods

Subjects undergo pre-planned biometry (IOL Master 700, Carl Zeiss) measurements before and after GAT on the day of pre-assessment (Axial length (AL), Anterior Chamber Depth (ACD), Lens Thickness (LT), ‘White-to-white’, Keratometry, Total Keratometry (TK)). Comparative analysis of AL and Keratometry values was performed. In addition assessments of ocular surface quality (OSQ) pre- and post- biometry was performed.

Results

A total of 40 eyes (20 adult patients, mean age 76-88 years) with a diagnosis of mild to moderate Primary Open Angle Glaucoma have been included so far (last update 29/02/24). The K readings showed a change from 0.02D to 1.14D but no significant changes in AL. The OSQ worsened in all cases, with these values persisting for up to 3 hours post-tonometry.

Conclusions

GAT can significantly affect Biometry readings and OSQ for up to 3 hours post-measurement. IOP measurement by GAT should be deferred until after Biometry in these patients. Wrong IOL Power could be a consequence of these changes with a potential IOL power calculation difference of up to 1D.