Related Experiment Video
Updated: May 12, 2026
09:03
Trabecular Meshwork Response to Pressure Elevation in the Living Human Eye
Published on: June 20, 2015
Corneal biomechanical properties affect Goldmann applanation tonometry in primary open-angle glaucoma
Bryan R Costin1, Gloria P Fleming, Paul A Weber
1*Department of Ophthalmology, William H. Havener Eye Institute, The Ohio State University Medical Center †Department of Biomedical Engineering, The Ohio State University, Columbus, OH.
Journal of Glaucoma
|April 23, 2013
Summary
Primary open-angle glaucoma (POAG) corneas are softer, leading to greater underestimation of intraocular pressure (IOP) by Goldmann applanation tonometry (GAT) compared to newer methods, independent of central corneal thickness (CCT). This impacts POAG treatment decisions.
Area of Science:
- Ophthalmology
- Biomechanical Engineering
- Glaucoma Research
Background:
- Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness.
- Accurate intraocular pressure (IOP) measurement is critical for POAG diagnosis and management.
- Corneal properties significantly influence IOP readings, necessitating investigation into their role in POAG.
Purpose of the Study:
- To investigate differences in corneal biomechanical properties between POAG patients and normal controls.
- To assess the impact of these biomechanical differences on intraocular pressure (IOP) measurements obtained by various tonometry methods.
- To determine if central corneal thickness (CCT)-matched controls adequately account for biomechanical variations in POAG.
Main Methods:
- Corneal topography, Goldmann applanation tonometry (GAT), dynamic contour tonometry (DCT), and corneal-compensated IOP (IOPcc) were performed.
- Corneal hysteresis and central corneal thickness (CCT) were measured using the Reichert ocular response analyzer (ORA).
- Data from 13 POAG eyes and 15 control eyes were compared using t tests.
Main Results:
- POAG subjects exhibited significantly lower corneal hysteresis compared to controls.
- The magnitude of difference between GAT and DCT/IOPcc (delta differences) was significantly greater in POAG eyes.
- Mean DCT and IOPcc values were significantly different between POAG and control groups, unlike mean GAT IOP.
Conclusions:
- Corneal biomechanical properties, specifically lower corneal hysteresis, are significantly different in POAG patients compared to controls, independent of CCT.
- Goldmann applanation tonometry (GAT) may underestimate IOP more significantly in POAG patients due to these biomechanical differences.
- These findings suggest that standard IOP measurements may require adjustment in POAG management, potentially influencing treatment decisions and patient outcomes.
Related Concept Videos
01:27Open Angle Glaucoma: Treatment
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...
01:25Glaucoma: Overview
Glaucoma is an eye condition characterized by increased intraocular pressure that damages the retina and optic nerve, leading to irreversible blindness if left untreated. The human eye has various components, including the cornea, iris, pupil, lens, and optic nerve. Aqueous humor is secreted by the epithelium of the ciliary body in the posterior chamber and flows through the trabecular meshwork and canal of Schlemm, maintaining normal intraocular pressure. The trabecular meshwork and the canal...
01:28Angle Closure Glaucoma: Treatment
Angle-closure glaucoma, or closed-angle glaucoma, is an eye condition where the iris bulges out and blocks the iridocorneal angle, resulting in a buildup of aqueous humor and increased intraocular pressure. Immediate medical attention is necessary due to the sudden onset of symptoms. The treatment for angle-closure glaucoma includes short-term and long-term approaches. Short-term treatment involves using eye drops like pilocarpine to lower intraocular pressure by increasing aqueous humor...