Abstract
Frequent intraocular pressure (IOP) measurements are desirable in the diagnosis and management of glaucoma. Most current tonometers utilize some form of corneal deformation to estimate the IOP, since trans-scleral tonometry suffers from loss of sensitivity. Tran-scleral and trans-palpebral tonometry, however, offer a pathway towards a non-invasive home tonometry. This article presents a mathematical model capturing the relationship between the IOP and the displacements imposed onto the sclera by externally applied forces. Similar to manual digital palpation tonometry, trans-scleral mechanical palpation makes use of two force probes that are advanced in a specific order and distance. Data from the applied forces and displacements, along with concurrent measurements of IOP is used to produce a phenomenological mathematical model. The experiments were carried out on enucleated porcine eyes. Two models are presented. Model 1 predicts IOP vs forces and displacements, while Model 2 predicts the baseline IOP (prior to applying the forces) as a function of the measured forces and displacements. The proposed models result in IOP errors of 1.65 mmHG and 0.82 mmHg, respectively. Model parameters were extracted using least-squares-based system identification methods. The results show that the proposed models can be used to estimate the baseline IOP with accuracy of ±1 mmHg over a pressure range of 10–35 mmHg, solely from measurement of tactile forces and displacements.
Original language | English (US) |
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Article number | 105864 |
Journal | Journal of the Mechanical Behavior of Biomedical Materials |
Volume | 142 |
DOIs | |
State | Published - Jun 2023 |
Keywords
- Eye palpation
- Eye pressure
- Eye stiffness
- Glaucoma
- Mathematical model
- System identification
ASJC Scopus subject areas
- Biomaterials
- Biomedical Engineering
- Mechanics of Materials