IOP is the only modifiable risk factor for glaucoma and, as such, accurate tonometry is of critical importance in the diagnosis and management of this disease. It is widely recognized that the current gold standard for measuring pressure, the Goldmann Applanation Tonometer (GAT), has considerable flaws. Goldmann, and other current tonometers, are significantly influenced by corneal properties such as rigidity and thickness. Though it has been shown that GAT provides clinically reliable measurements in eyes with “average” corneas, we now know that many corneas vary more significantly from average than previously thought.
Numerous Studies have shown that thicker corneas overstate IOP values and thinner corneas understate IOP. However, thickness does not adequately describe corneal biomechanical properties, making the use of CCT-based correction algorithms questionable at best. In fact, researchers have concluded that correcting IOP based on CCT can lead not only to errors in the magnitude, but also in the direction of the adjustment.
Reichert’s 7CR Auto Tonometer + Corneal Response Technology takes corneal biomechanical properties into consideration, providing Corneal Compensated IOP (IOPcc) – a pressure measurement that is significantly less affected by the cornea than other methods of tonometry. The instrument’s unique ability to simultaneously provide a Goldmann- correlated IOP measurement (IOPg) and IOPcc, provides clinicians with a better understanding of patient tonometry values, enhancing clinicians ability to make critical diagnosis and treatment decisions.