Corneal and Epithelial Thickness Measurements: Comparability between two Different Ocular Coherence Tomography...

Area of Science:

• Ophthalmology
• Medical Imaging
• Corneal Science

Background:

• High-frequency ultrasound and anterior segment optical coherence tomography (OCT) are used for diagnosing keratoconus and planning refractive surgery.
• Anterior segment OCT is increasingly utilized for monitoring keratoconus progression, hydrops, and epithelial healing.
• Comparing different OCT devices is crucial for consistent diagnostic and surgical planning data.

Purpose of the Study:

• To compare epithelial and pachymetric thickness parameters from two different Fourier-domain OCT devices.
• To determine if measurements from two OCT devices can be used interchangeably for corneal and epithelial thickness analysis.
• To assess the interchangeability of OCT measurements in normal and post-SMILE eyes.

Main Methods:

• Retrospective chart review of 24 normal and 32 post-SMILE eyes.
• Corneal and epithelial thickness maps were acquired using two OCT devices: Cirrus 5000 and Avanti RTVue 100.
• Key parameters analyzed included minimum corneal thickness (Pachy min), minimum minus median corneal thickness (Pachy min-med), and maximum epithelial thickness (Epi max).

Main Results:

• Pachy min and Epi max measurements showed good agreement between the two OCT devices (ICC 0.906 and 0.839).
• Significant correlations were found for Pachy min, Pachy min-med, and Epi max in normal eyes.
• In post-SMILE eyes, only Pachy min and Epi max measurements showed significant correlation between devices.

Conclusions:

• Anterior segment OCT is valuable for quantitative corneal and epithelial thickness measurements.
• Significant differences exist in measurements between OCT devices.
• OCT device measurements should not be used interchangeably due to device-specific variations.