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Comparing Repeatability and Agreement between Commonly Used Corneal Imaging Devices in Keratoconus
Lize Angelo1, Akilesh Gokul1, Charles McGhee
1Department of Ophthalmology, University of Auckland, Auckland, New Zealand.
Summary
Repeatability of keratometry and pachymetry measurements for keratoconus management varied between devices. The Pentacam and Medmont showed better repeatability for keratometry, while the Revo excelled in thinnest corneal thickness measurements. Devices should not be used interchangeably.
Area of Science:
- Ophthalmology
- Corneal Imaging
- Diagnostic Technology
Background:
- Keratometry and pachymetry are crucial for diagnosing and monitoring keratoconus.
- Several corneal imaging devices are available, necessitating comparative analysis for clinical utility.
- Accurate measurements are vital for effective management in both primary and secondary eye care settings.
Purpose of the Study:
- To evaluate the repeatability and agreement of a Placido disc-based videokeratoscope against spectral-domain optical coherence tomography and Scheimpflug tomography.
- To compare measurement precision and inter-device agreement for key keratoconus diagnostic parameters.
- To assess the suitability of these devices for keratoconus management in different healthcare settings.
Main Methods:
- A prospective, single-center study involving 110 eyes of 110 keratoconus patients.
- Central corneal thickness, thinnest corneal thickness (TCT), and keratometry parameters (Kmax, Kmean, Ksteep, Kflat) were measured using three devices: a Placido disc-based videokeratoscope, spectral-domain OCT, and Scheimpflug tomography.
- Intraobserver repeatability was assessed through three measurements per device for each parameter.
Main Results:
- The Pentacam demonstrated the best repeatability for central corneal thickness and most keratometry parameters.
- The Medmont showed better repeatability than the Revo for keratometry parameters.
- The Revo exhibited the highest repeatability for thinnest corneal thickness (TCT).
- Intraclass correlation coefficients exceeded 0.94 for all parameters across all devices.
- Agreement between devices was generally poor, with good agreement noted only between Pentacam and Medmont for Kflat.
Conclusions:
- The Pentacam and Medmont offer superior repeatability for keratometry measurements compared to the Revo.
- The Revo provides the highest repeatability for TCT, potentially aiding in monitoring disease progression and assessing corneal cross-linking.
- Significant disagreement exists between the devices, precluding their interchangeable use in clinical practice.
- Careful consideration of device-specific performance is necessary for accurate keratoconus diagnosis and management.
