Measuring Eye Pressure for Glaucoma

Nov 11, 2020 | Eye Care

Corneal Hysteresis is a relatively new term used when referencing Glaucoma.  What is it, and what does it mean?

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).”

The gold standard in measuring glaucoma has long been the Goldmann Applanation Tonometry (GAT).  This is the blue light test eye doctors administer after numbing the eye with yellow dye drops.  The yellow dye glows under a blue light. Technology has been changing and after 70 years of GAT so maybe CH, corneal compensated IOP (IOPcc) and the Ocular Response Analyzer could replace it.

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.”  What test the doctor uses is secondary to actually getting the patients in the office for screening.  Glaucoma, as in many eye diseases can happen without notice.

A common mistake people make with glaucoma is thinking it can be treated with marijuana.  Although marijuana can lower pressure in the eye, the reduction is temporary at best, and not considered an effective treatment.


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