In Vivo Biomechanical Characteristics of Human Corneas With Phase-Decorrelation OCT

The mechanical properties of the cornea contribute to the cornea's morphological response to surgery as well as the pathogenesis of ectatic disease states and the effects of corresponding treatment. Phase-decorrelation optical coherence tomography (PhD-OCT) is a technique which uses information acquired using a standard OCT system and, similar to dynamic light scattering techniques, calculates the temporal autocorrelation of the light backscattered from the cornea. This work seeks to assess PhD-OCT measurement repeatability and key markers in a normal clinical population.

This study recruited patients who presented for refractive surgery evaluation at the Cleveland Clinic Cole Eye Institute and were deemed to be candidates for laser vision correction. In addition to standard of care assessments, PhD-OCT imaging was performed on each eye of these participants in triplicate using a commercially available anterior segment OCT scanner. Interclass correlation was calculated for repeated measurements and the PhD-OCT measurements from these normal corneas were analyzed by corneal depth and regressed against clinically relevant variables.

PhD-OCT consistently exhibited an anterior to posterior gradient in the measured mobility property with lower mobility/stiffer properties in the anterior stroma. PhD-OCT measurements also demonstrated very good repeatability (with an interclass correlation of 89%). Corneal thickness was not a significant contributing factor to the PhD-OCT measurements in normal eyes. PhD-OCT measurements varied significantly between some groups defined by age or sex, suggesting that there may be microstructural differences between these groups.

PhD-OCT is a repeatable and unique measurement that can provide spatially resolved insight into a patient's corneal microstructure mobility. This approach can be implemented on existing clinical hardware.