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Published on: October 21, 2022
Central Corneal Thickness Reproducibility among Ten Different Instruments.
Luisa Pierro1, Lorenzo Iuliano, Marco Gagliardi
1*MD †PhD Department of Ophthalmology, Vita-Salute University, San Raffaele Scientific Institute, Milan, Italy (LP, LI, MG, FB); Vita-Salute San Raffaele University, Milan, Italy (AA); and Cornea and Ocular Surface Unit, San Raffaele Scientific Institute, Milan, Italy (PR).
This study compared ultrasonic and optical devices for measuring central corneal thickness (CCT). While optical instruments showed excellent reproducibility, a scale bias between devices may impact CCT monitoring, suggesting consistent device and operator use.
Area of Science:
- Ophthalmology
- Biomedical Optics
- Medical Instrumentation
Background:
- Accurate measurement of central corneal thickness (CCT) is crucial for diagnosing and managing various ocular conditions.
- A wide array of optical and ultrasonic instruments are available for CCT assessment, each with potential variations in accuracy and reproducibility.
Purpose of the Study:
- To evaluate the agreement between a single ultrasonic (US) instrument and nine optical devices for measuring central corneal thickness (CCT).
- To assess the intra- and inter-operator reproducibility of these CCT measurement devices.
Main Methods:
- An observational, cross-sectional study involving 28 healthy eyes measured twice by two masked operators.
- Utilized seven spectral-domain optical coherence tomography (SD-OCT) devices, one time-domain OCT, one Scheimpflug camera, and one US-based instrument.
- Evaluated reproducibility using intraclass correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman analysis; instrument agreement assessed via ANOVA and structural equation modeling.
Main Results:
- Mean CCT varied across instruments (536 ± 42 μm to 577 ± 40 μm).
- High instrument-to-instrument correlation was observed (0.852-0.995), with specific OCT devices showing the strongest agreement.
- Optical devices demonstrated excellent intra- and inter-operator reproducibility, unlike the US-based device; Bland-Altman analysis indicated low operator bias.
Conclusions:
- Optical instruments exhibit strong intra- and inter-operator reproducibility for CCT measurement.
- A potential scale bias exists between different CCT measurement devices, which could affect long-term monitoring.
- Consistent use of the same device and operator is recommended for optimal central corneal thickness monitoring.
