Ocular Response Analyzer® G3 (ORA) is the only device that measures Corneal Hysteresis (CH), which has been shown to be a superior predictor of glaucoma progression. Corneal Hysteresis is an indication of the biomechanical properties of the cornea differing from thickness or topography, which are geometrical attributes.
In addition to Corneal Hysteresis, Ocular Response Analyzer G3 provides Corneal Compensated Intraocular Pressure (IOPcc), a better indication of the true pressure, proven to be less influenced by corneal properties than Goldmann or other methods of tonometry. This reading is also available in the Reichert 7CR Auto Tonometer which gives IOPcc as well as an IOPg reading.
How the G3 ORA has a positive impact on clinical practice
Despite improvements in treatment options, Glaucoma remains a leading cause of blindness with no cure. Diagnosing and predicting glaucoma progression is challenging due to the wide variety of risk factors, all with relatively low specificity. As such, it is essential that we consider glaucoma to be a multi-factorial disease with numerous risk factors that should be taken into account.
The Ocular Hypertension Treatment Study (OHTS) put central corneal thickness (CCT) on the map due to the surprise finding that CCT was independently and strongly related to glaucoma risk. This was the first time that a corneal parameter was shown to be related to development of glaucoma. Now, we have ample evidence that Corneal Hysteresis (CH) is even more important that CCT in the assessment of glaucoma risk.
Studies have shown CH measurements are significantly, and independently, associated with glaucoma risk. Eyes with lower CH tend to progress more rapidly. Prospective longitudinal studies have demonstrated that baseline CH predicts the rate of future visual field loss in glaucoma suspects and patients. The biggest challenge in managing glaucoma is predicting future progression. It typically takes 5-6 visual field test results over a period of months or years to establish progression rates. Different glaucoma patients with similar risk factors may progress at dramatically different rates. This is unnerving to patients and clinicians alike. Ideally we would allocate resources to those who require it most.
Since CH has been shown to be more predictive of future visual field progression than other factors, including this parameter in assessment of glaucoma risk will improve glaucoma decision making and facilitate earlier intervention to improve visual outcomes.
What differentiates the G3 ORA to other alternatives in the market?
No other device can measure corneal hysteresis. No other tonometer, aside from the Reichert 7CR auto tonometer, can provide an IOP measurement that is compensated for corneal biomechanics (IOPcc). These are patented Reichert parameters.
“There are so many positives to adding the ORA to our practice. The doctors and staff agree that it was the best equipment purchase we have made in years. We are completely confident in the IOP measurements instead of Goldmann. Just the aid in practice flow efficiency alone has been worth it.
The Corneal Hysteresis measurement is now a crucial part of our glaucoma decision making for ocular hypertensive patients, changes in treatment for current glaucoma patients, and in secondary glaucomas (pseudoexfoliation/pigment dispersion). In particular, it has really increased our ability to recognize patients who are at higher risk of normal tension or low tension glaucoma. There are a lot of patients in the world who are not being treated for glaucoma (but need to be), but on the other side there are people who are being treated and may not need to be. Studies have demonstrated the emotional and financial burdens an unnecessary diagnosis of glaucoma has on patients. The better we are able to understand this multifactorial disease, the better patient care we can provide. Our patients sincerely appreciate our ability to collect as much data as possible before committing them to a life-long treatment regimen.” David Cage, OD. Erie, PA, USA