Comparative Analysis Of The Agreement Of Keratometry Readings Across Three Devices In Varying Stages Of Keratoconus
Published 2024 - 42nd Congress of the ESCRS
Reference: FP05.07 | Type: Free paper | DOI: 10.82333/g06q-n984
Authors: Konstantinos Papadopoulos* 1 , Miltiadis Balidis 2 , Kareem Mahgoub 3 , Mohamed Elalfy 4 , Artemis Matsou 3
1Department of Ophthalmology ,General Hospital of Imathia (Unit of Veroia),Veroia,Greece;Corneoplastic Unit,Queen Victoria Hospital NHS Foundation Trust,East Grinstead,United Kingdom, 2Ophthalmica Eye Center,Thessaloniki,Greece, 3Corneoplastic Unit,Queen Victoria Hospital NHS Foundation Trust,East Grinstead,United Kingdom, 4Corneoplastic Unit,Queen Victoria Hospital NHS Foundation Trust,East Grinstead,United Kingdom;The Research Institute of Ophthalmology,Cairo,Egypt
Purpose
To evaluate the agreement of keratometry (K) readings obtained from three different devices - Pentacam HR (Oculus Optikgeräte GmbH), MS-39 (CSO) and IOL-Master 700 (Carl Zeiss Meditec AG)- across various grades of keratoconus (KC).
Setting
Outpatient clinic of the Corneoplastic Unit of Queen Victoria Hospital, East Grinstead. Measurements were obtained between July 2023 and September 2023.
Methods
In this cross-sectional inter-device agreement study 168 eyes of 98 KC patients were enrolled and categorized into four stages (1-4) by maximum keratometry (Kmax) of Pentacam HR: < 48.00, 48.00-53.00, 53.00-58.00, and > 58.00 diopters (D). We assessed flat keratometry (K1) and steep keratometry (K2) readings, including the equivalent keratometry readings (EKR) from Pentacam HR.
Results
For mild KC (stages 1-2), all devices showed substantial agreement (ICC 0.85-0.94, p < 0.001), which diminished to moderate in more advanced stages (ICC 0.39-0.88, p < 0.001). A similar trend was observed with K2 readings, showing high consistency in early stages (ICC 0.67-0.9, p < 0.001) and lower in stages 3-4 (ICC 0.22-0.78, p < 0.001). Pentacam HR consistently reported higher K1 values than the MS-39, particularly in severe KC (difference of 0.49/2.28 D, stages 3/4 respectively, p < 0.05). For Kmax > 53.00 D, IOL-Master 700 recorded significantly higher K2 values than MS-39 (differences of 0.81/2.35/4.2 D, stages 2/3/4 respectively, p < 0.001). The EKR formula consistently yielded flatter K values compared to the other Κ readings.
Conclusions
The study indicates good agreement among devices for mild KC cases, but only moderate in severe stages. It suggests that K readings from these devices should not be used interchangeably in KC, especially as the condition progresses.