SPOTLIGHT ON TECHNOLOGY & TECHNIQUE

ORA’s unique tricks for measuring pressure

Gauging corneal hysteresis and corneal-compensated IOP are hallmarks of the line.

By Robert Stoneback, Associate Editor

For Felipe Medeiros, MD, the Ocular Response Analyzer line of tonometers contains two key features: the ability to gauge corneal hysteresis (CH) and the patented corneal-compensated IOP (IOPcc) measurement.

Reichert, manufacturer of the ORA, states that IOPcc is less dependent on corneal properties. If a cornea is biomechanically “tougher” or “weaker,” it can throw off pressure measurements. This is not the case with the IOPcc measurement system, according to Dr. Medeiros, of the University of California, San Diego’s Shiley Eye Institute.

Reichert’s ORA G3 was released in August. Among its features are measuring corneal-compensated IOP and corneal hysteresis.

CH AND VISION LOSS

Corneal hysteresis, defined as the difference between the eye’s inward and outward pressure values, is an important risk assessment for glaucoma, Dr. Medeiros says. He and other investigators have conducted several studies “showing the importance of corneal hysteresis as a factor predicting the risk of glaucoma development and progression.”

In one of Dr. Medeiros’ studies published in Ophthalmology in 2013, he and his colleagues showed how corneal hysteresis could be used in determining the speed of glaucoma progression in patients. Studying 114 eyes in 68 glaucoma patients, the researchers discovered that each 1 mm Hg decrease in corneal hysteresis was associated with a faster rate of visual field index decline, at a rate of 0.25% VFI a year. Eyes with a higher rating of corneal hysteresis were at a lower risk of vision loss.

Having that extra information leads to more accurate risk assessment, and ultimately a more thorough treatment for patients, says Dr. Medeiros.

Reichert has provided research support for Dr. Medeiros, according to the study. The ORA is the sole instrument of its kind.¹

TESTING THE ORA LINE

The new ORA G3 model, released in August, can connect with and export data to electronic medical record systems, making measurements more reliable and reproducible, Dr. Medeiros says.

Mitsugu Shimmyo, MD, of New York City’s Shimmyo Group, beta-tested the ORA G3 at his clinic prior to the device’s release. In his opinion, the faster G3 system is the better choice for a general ophthalmology practice without research interest, as it can collect data more quickly. This also makes it more conducive to higher patient volume and busy practices.

The G3, Dr. Shimmyo says, is “more like an autorefractor in size and speed of use,” and its exams are more repeatable due to improvements to the measurement system and software.

Dr. Shimmyo, who co-authored many papers using the previous ORA models, believes that the older G2 is more appropriate for research and academia since it archives patient data and includes many additional research parameters that can be exported and analyzed.

TOUCH SCREENS AND NONCONTACT TESTING

The ORA G3’s touch screen interface is designed so that a fully automated alignment and measurement can be displayed and initiated with a single button press. The G3 can simultaneously display measurements for Reichert’s patented IOPcc, corneal hysteresis, Goldman correlated IOP (IOPg) and Waveform Score (WS).

Like its predecessor, the G3 is a noncontact tonometer, meaning patients do not place their eye directly on the device. This reduces the risk of cross contamination and eliminates the need to sterilize the machine after use.

Patient comfort is also increased due to a patented air pulse feature. The pulse is customized for each eye being measured, making it as soft as possible, according to Reichert.

BILLING, REIMBURSEMENT

The CPT code 92145 is used to report corneal hysteresis tests. The Medicare reimbursement for corneal hysteresis testing is $15.73, bilateral.

Those numbers can add up if used hundreds of times in a month, as Dr. Medeiros does in his clinic.

“I use that routinely in a number of patients,” he says.

Reichert’s ORA line of tonometers had a home in Dr. Medeiros’ clinic before it even reached the market.

He says he was probably one of the first people to use the devices, starting when it was in development around 2003. As he validated the technology and its ability to measure intraocular pressure, he became more comfortable incorporating it into his business. OM

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