Abstract
Purpose: :
To analyze corneal graft thickness in surgical tissue from the eye-bank with both anterior-segment optical coherence tomography (AS-OCT) and ultrasound (US) pachymetry. Thorough understanding of corneal thickness (CT) measurement is essential for analysis of endothelial keratoplasty (EK) tissue processing methods and for correlations of tissue thickness with EK patient outcomes.
Methods: :
Prospective assessment was performed on 37 corneas, which underwent lamellar graft dissection using the standard eye-bank protocol for pre-cut EK donor tissue. Central and peripheral CT was measured by US with the cornea mounted on an artificial anterior chamber. The corneas were then transferred to a viewing chamber for CT measurement by AS-OCT. Paired T-tests and Pearson correlation analyses were performed to compare AS-OCT and US measurements.
Results: :
There was a statistically significant difference in CT measured by AS-OCT versus US in eye-bank prepared tissues (mean: 170 µm vs. 183 µm, respectively, p=0.05). There was a strong positive correlation in AS-OCT and US central CT (r=0.63, p<.0001). Correlation of peripheral corneal thickness measurements by AS-OCT and US was weak to moderate (r range=.20-.54). Additionally, there was poor correlation of pre-cut to post-cut CT (r=0.06, p=.73).
Conclusions: :
Similar to in vivo differences between CT measured by AS-OCT versus US (that range from 6-51 µm thinner by AS-OCT), AS-OCT measurements of EK-prepared tissue averaged 13 µm thinner than US. Given the growing interest in the effect of EK graft thickness on patient outcomes, it is important to understand the relationship between the measurements obtained by devices commonly used for assessment of EK donor corneas.
Keywords: cornea: clinical science • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • transplantation