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Individual-specific tonometry on porcine eyes
Leo K K Leung1, Match W L Ko1, David C C Lam1
1The Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Hong Kong.
Medical Engineering & Physics
|November 9, 2013
Summary
A new tonometer measures intraocular pressure (IOP) corrected for corneal stiffness, improving accuracy. This innovation addresses limitations in current glaucoma diagnosis tools by accounting for individual corneal variations.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Materials Science
Background:
- Intraocular pressure (IOP) is crucial for glaucoma diagnosis and management.
- Current tonometry methods, like Goldmann Applanation Tonometer (GAT), are influenced by corneal properties, specifically corneal stiffness.
- This influence is not accounted for in standard IOP measurement devices, leading to potential inaccuracies.
Purpose of the Study:
- To develop and evaluate a novel instrumented non-invasive indentation tonometer.
- To measure intraocular pressure corrected for corneal stiffness (IOPIST).
- To assess the accuracy of the new tonometer compared to traditional methods in accounting for corneal variations.
Main Methods:
- Characterized inter-individual corneal stiffness variations in 12 ex vivo porcine eyes.
- Utilized a manometer to set true intraocular pressure (IOPT) in porcine eyes.
- Employed a new indentation tonometer to measure IOP, incorporating corneal stiffness correction.
Main Results:
- Porcine corneal stiffness varied significantly (0.045 to 0.253 N/mm).
- Without stiffness correction, Goldmann Applanation Tonometer (GAT) measurements showed errors up to 8mmHg at 15mmHg IOPT, increasing with higher pressures.
- The new tonometer (IOPIST) demonstrated significantly smaller errors (1.82±1.70mmHg) across a range of IOPT (12-40mmHg) when corneal stiffness was accounted for.
Conclusions:
- The developed indentation tonometer successfully corrects for inter-individual variations in corneal stiffness.
- This new method offers a more accurate IOP measurement, crucial for effective glaucoma diagnosis and management.
- The IOPIST represents a significant advancement over traditional tonometry by integrating corneal biomechanical properties.
