Purpose To explore the probability and variation in biomechanical measurements of rabbit cornea by Pentacam.
Methods a new method of measure corneal biomechanics, by imaging anterior segment of the model imitating the intact eye at various posterior pressures, was developed. Eight freshly enucleated, New Zealand White rabbit eyes were investigated in normal hydrated state. The isolated corneas were mounted on the Barron artificial chamber and images of the anterior segment were taken at posterior pressures of 15, 30, 45, 60, and 75 mmHg by Pentacam. The repeatability and reliability of the parameters including central corneal thickness (CCT), anterior chamber depth (ACD) and volume (ACV), corneal volume (CV) were evaluated at each posterior pressure. All the variations of the parameters at the different posterior pressures were calculated.
Results In the model, similar high-quality images of anterior segment of rabbit eyes were taken by Pentacam. All parameters including CCT, ACV, ACD, CV showed good intra-observer reliability (Cronbach's alpha; intra-class correlation coefficient, α, ICC > 0.96) and repeatability. With the increase of posterior pressures, the ratio of CCT decreased linearly and the bulk modulus gradually reduced to a platform. The increase of ACD was almost linear with the posterior pressures elevated.
Conclusions Pentacam was a valuable tool to investigate the biomechanics of the cornea. The posterior pressure 2-10 kPa (15-75 mmHg) range produced small viscoelastic deformations and nearly linear pressure-deformation response in the rabbit cornea.