Anyone who has gone to the eye doctor for a compete exam has been screened for glaucoma. The test is memorable as the doctor uses numbing drops that are stingy, sticky, and yellow. Known as the Goldmann Applanation Tonometry (GAT), it “has been used for nearly 70 years and is considered the reference standard for IOP [eye pressure] measurement”. However, for the past few years eye care professionals are considering a relatively new term, Corneal Hysteresis (CH) when managing glaucoma in patients.
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).”
Technology advancement in optometric care has been phenomenal. Yet replacing the GAT has been slow. Perhaps the time has come for CH, corneal compensated IOP (IOPcc) and the Ocular Response Analyzer to become the new standard.
Regardless of which tests eye care professionals choose for measuring glaucoma, the larger issue is getting patients to visit their office for screening. Glaucoma does not often show early symptoms, and about 3 million people have glaucoma according to the CDC. Moreover, only 50% of those people are diagnosed. That leaves another 1.5 million people at risk for blindness.
According to the CDC, “about 3 million Americans have glaucoma. 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.” Eye conditions that in their early stages are symptomless and painless like glaucoma may strike without a patient knowing. Early detection and treatment are crucial if one wants to fight to keep one’s precious sight.