Comparison of central corneal thickness measurements using three different imaging devices

Area of Science:

• Ophthalmology
• Biomedical Optics
• Medical Device Technology

Background:

• Accurate central corneal thickness (CCT) measurement is crucial for ophthalmic diagnostics and surgical planning.
• Various devices exist for CCT assessment, but their comparative performance and agreement require thorough evaluation.

Purpose of the Study:

• To compare central corneal thickness (CCT) values obtained from three distinct measurement devices.
• To evaluate the inter-device agreement for CCT measurements in healthy eyes.

Main Methods:

• Retrospective analysis of CCT data from 120 eyes of 60 healthy individuals.
• Measurements were performed using an optical biometer (AL-Scan), spectral-domain optical coherence tomography (SD-OCT), and ultrasonic pachymetry (UP).
• Bland-Altman analysis was employed to assess the agreement between the measurement methods.

Main Results:

• Mean CCT values were 532.4μm (AL-Scan), 549μm (UP), and 547μm (SD-OCT).
• Significant differences were found between AL-Scan and both UP (17.15±8.42μm) and SD-OCT (15.30±9.52μm).
• A close correlation was observed between all three CCT measurement methods, with minimal difference between UP and SD-OCT (1.85±8.78μm).

Conclusions:

• While all devices showed good correlation, AL-Scan significantly underestimated CCT compared to UP and SD-OCT.
• Clinicians must recognize that different devices yield varying CCT results.
• To ensure consistent patient management, especially pre-refractive surgery, CCT assessment should utilize the same device consistently.