ESCRS - PO491 - Comparison Of Anterior Corneal Aberrometry, Keratometry And Pupil Size With Scheimpflug Tomography And Ray Tracing Aberrometer

Comparison Of Anterior Corneal Aberrometry, Keratometry And Pupil Size With Scheimpflug Tomography And Ray Tracing Aberrometer

Published 2022 - 40th Congress of the ESCRS

Reference: PO491 | Type: ESCRS 2022 - Posters | DOI: 10.82333/ch48-h062

Authors: Zahra Ashena* 1 , Sean Gallagher 2 , Hasan Naveed 3 , Mayank Nanavaty 2

1Ophthalmology,Queen's Hospital, Romford,London,United Kingdom, 2Ophthalmology,Sussex Eye Hospital,Brighton,United Kingdom, 3OPhthalmology,Sussex Eye Hospital,Brighton,United Kingdom

Purpose

This study aimed to assess the anterior corneal wavefront aberrations, keratometry, astigmatism vectors and pupil size between Pentacam HR®(Oculus Optikgeraete GmbH) and iTrace® (Tracey Technologies Corp.). 

Setting

Sussex Eye Hospital, University Hospitals Sussex NHS Foundation Trust, UK

Methods

In this observational study, 100 eyes of 50 healthy volunteers were scanned in mesopic light condition with a Pentacam HR® and iTrace®. Anterior corneal aberrations (spherical aberration (Z40), vertical coma (Z3-1), horizontal coma (Z3+1)), keratometry in the flattest (K1) and steepest meridian (K2), mean astigmatism, astigmatic vectors (J0 and J45), and pupil size were measured. 

Results

We found a significant difference in Z40 (Pentacam®: +0.30µm±0.11 and iTrace®: -0.03µm±0.05; p<0.01) with no correlation between the devices (r=-0.12, p=0.22). The devices were in complete agreement for

Z3-1(p=0.78) and Z3+1 (p=0.39) with significant correlation between the machines (r=-0.38, p<0.01 and r=-0.6, p<0.01). There was no difference in K1, K2 and mean astigmatism. J0 was negative with both devices (against-the-rule astigmatism), but there was no correlation. J45 was negative with the Pentacam HR® (more myopic oblique astigmatism) but significantly correlated between the devices. Pupil size was smaller with Pentacam HR® (P<0.01).

Conclusions

In conclusion, these devices cannot be used interchangeably. Corneal Z40 was significantly different with more negative Z40 with iTrace® compared to Pentacam HR®. iTrace® operates with lower illumination giving larger pupil size than Pentacam HR®, which uses intense blue light during measurement. No correlation was found for J0 and Pentacam HR® had a trend to record more negative J45 (myopic oblique astigmatism).