Health Problem: Glaucoma is a group of ocular disorders that causes progressive damage to the optic nerve, which results in loss of vision. Glaucoma is the second leading cause of blindness worldwide, with as many as 6 million people blind in both eyes due to this condition. In the United States, more than 3 million people have glaucoma, among whom up to half are unaware that they have the disease.
Technology Description: Glaucoma causes changes in the physical properties of the eye that tend to make the cornea less flexible, which reduces corneal hysteresis (elasticity) and increases corneal stiffness. Corneal hysteresis is measured with the Optical Response Analyzer (Reichert Technologies), which monitors the reflection of light from the surface of the cornea while it applies a brief puff of air to the cornea. A lower value of corneal hysteresis is considered indicative of the presence of glaucoma or a greater likelihood of developing glaucoma.
Controversy: A wide array of tests have been developed for detection and monitoring of glaucoma, including measurement of intraocular pressure (IOP) and corneal central thickness. Measurement of corneal hysteresis may not provide useful additional information and the diagnostic accuracy of this test has not been fully elucidated.
Key Questions:
- Does measurement of corneal hysteresis provide accurate diagnostic information in patients who have suspected glaucoma?
- Does information obtained from measurement of corneal hysteresis improve glaucoma management or outcomes in patients with the disease?
- Is measurement of corneal hysteresis safe?
- Have definitive patient selection criteria been established for measurement of corneal hysteresis?
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