For the past few years, when eye care professionals attend any continuing education courses on glaucoma, there is one relatively new term they may hear: Corneal Hysteresis.
Corneal Hysteresis is a value that tells us the “shock-absorbing ability” of the eye and it is measured by an Ocular Response Analyzer. A CH below 10 is said to be low, that is bad thing. A CH of above 10 is said to be high, that is a good thing. “Essentially, eyes that are good shock absorbers (high CH) are less likely to develop glaucoma and less likely to experience glaucomatous progression. Conversely, eyes that are poor shock absorbers (low CH) are more likely to develop glaucoma and [have] disease progression. CH reflects how an eye responds to stress (elevated IOP) and whether the eye experiences the brunt of that stress (low CH) or is able to dissipate the energy and protect the optic nerve (high CH).”
Eye doctors are considering CH more frequently when managing a patient’s glaucoma. Although the Goldmann Applanation Tonometry (GAT) has been considered the standard accepted test for over 70 years, CH, corneal compensated IOP (IOPcc) and the Ocular Response Analyzer may replace it. Advances in eye technology have become more sophisticated, but the jury is still out as to when it will overtake the GAT.
Regardless of which test is used, eye doctors can all agree that getting the patient into the office is more important. Glaucoma, as many eye diseases, show very few early symptoms. Tests performed during comprehensive exams is the single best way to diagnose and manage.
“About 3 million Americans have glaucoma” according to the CDC It is the second leading cause of blindness worldwide. Open-angle glaucoma, the most common form, results in increased eye pressure. There are often no early symptoms, which is why 50% of people with glaucoma don’t know they have the disease.”