Interdevice variability of central corneal thickness measurement

Area of Science:

• Ophthalmology
• Biomedical Optics
• Medical Device Technology

Background:

• Accurate central corneal thickness (CCT) measurement is crucial for ophthalmic diagnostics and surgical planning.
• Variability in CCT measurements between devices can lead to diagnostic errors and suboptimal clinical decisions.
• Understanding inter-device variability is essential for ensuring reliable patient care.

Purpose of the Study:

• To evaluate and compare the variability of central corneal thickness (CCT) measurements across a wide range of devices.
• To identify which CCT measurement technologies and specific devices exhibit the highest accuracy and lowest variability.
• To assess the clinical implications of inter-device variability in CCT measurements.

Main Methods:

• Consecutive CCT measurements were performed on 122 normal corneas from 61 subjects.
• Seven different devices utilizing Scheimpflug, Ultrasound (US), and Optical Coherence Tomography (OCT) technologies were employed.
• Device performance was assessed by calculating the deviation of each device's CCT measurement from the mean CCT value per eye.

Main Results:

• Optical Coherence Tomography (OCT) devices, particularly Cirrus OCT, demonstrated the lowest deviation from the mean CCT.
• Deviations ranged from 4.2±3.2 μm (Cirrus OCT) to 12.8±5.0 μm (Topcon noncontact specular microscopy).
• Ultrasound pachymetry showed substantial maximum differences (up to 120 μm) compared to other devices.

Conclusions:

• Significant inter-device variations in CCT measurements exist, potentially leading to under- or overestimation.
• Relying on a single CCT measurement device may result in inappropriate clinical and surgical recommendations.
• OCT technology offers superior accuracy for central corneal thickness measurement compared to other tested methods.