Development of Eye Phantoms for Mimicking the Structural Deformation of the Human Cornea Accompanied With Intraocular Pressure Alteration

Abstract

We developed a fully continuous eye phantom to better understand structural deformation of the cornea under varying intraocular pressure (IOP). The IOP-induced deformation and tension of the eye phantom were investigated using optical coherence tomography and non-contact tonometer readings, respectively. A fixed-cornea eye phantom, which featured a soft cornea, was also used for comparison. We evaluated the corneal structural changes between the two different types of eye phantoms by estimating the central corneal thickness (CCT) and corneal radius of curvature (CRC). For the eye phantom with an initial CCT of 0.55 mm, which is close to the average human CCT, CRC of the fully continuous eye phantoms showed a positive correlation to true IOP, while the CRC of a fixed-cornea eye phantom had a negative correlation. Non-contact tonometry readings for fixed-cornea eye phantoms were higher than those of full-eye phantoms due to the structural and mechanical characteristics. Considering the results from in vitro studies on enucleated human eyeballs, a fully continuous eye phantom is a more suitable choice for mimicking human IOP than a fixed-cornea eye phantom. Use of a more reliable eye phantom for accurate estimation of IOP using tonometry may eventually improve the accuracy of glaucoma screening.