A Japanese study has demonstrated that medically controlled glaucomatous eyes have biomechanical properties distinct from healthy eyes. These eyes had easier applanation and steeper deformation, highlighting the cornea’s susceptibility to deformation. Researchers believe this could increase the risk of optic nerve damage through an underestimation of intraocular pressure (IOP) and biomechanical vulnerability of the globe.

Using a dynamic Scheimpflug analyzer, the team retrospectively compared eight biomechanical parameters in 47 glaucomatous eyes and 75 healthy eyes and controlled for IOP, central corneal thickness, age and axial length. The study found negative correlation between glaucoma and three parameters (time of the first and second applanation and radius of curvature at maximum deformation) consistently, which indicated larger deformability of the cornea. Negative correlation between glaucoma and whole eye movement indicated smaller eye movement in glaucomatous eyes.

Researchers propose that biomechanical properties of the cornea could have a more significant impact on glaucoma susceptibility than corneal thickness, which is only one aspect of biomechanical properties. Measuring these would not only accurately measure IOP but also predict IOP-induced optic nerve damage and could optimize IOP-lowering therapy to halt it. The study concludes that further exploration of ocular biomechanical parameters could leader to better understanding glaucoma’s pathophysiology and more accurate risk assessments. 

Miki A, Yasukaura Y, Weinreb R, et al. Dynamic Scheimpflug ocular biomechanical parameters in healthy and medically controlled glaucoma eyes. Glaucoma. May 15, 2019. [Epub ahead of print].