Steven Feldon, M.D., director of the Eye Institute at the University of Rochester Medical Center, has received U.S. patent # 6,776,756 for a new tonometer, a device that doctors and optometrists use to measure pressure inside the eye. When pressure becomes too high, the fibers of the optic nerve begin to die, and patients develop glaucoma, which can leave patients blind if left untreated or undetected in its early stages.

Feldon previously developed the Tono-penTM, a portable tonometer that doctors have used worldwide to measure eye pressure in millions of patients. The easy-to-use device, about the size of a pen, quickly became the most widely used portable tonometer for physicians, allowing a health professional with minimal training to do the test on a patient virtually anywhere. Doctors in emergency rooms and clinics typically carry the devices in their pockets as they move from patient to patient.

The new portable device, called the NewtonTM, keeps the portability of the TonopenTM but boosts the accuracy of the device to a level previously seen only in bulky, more expensive systems. While the TonopenTM is ideal for screening many patients, it's used more as a screening tool to identify patients whose pressures initially appear high. These patients are then evaluated more thoroughly with other technologies. The high precision of the NewtonTM makes further measurements unnecessary.

"We wanted an instrument that is as accurate as the device that has long been the gold standard, the Goldmann device, but with the portability of the TonopenTM," says Feldon.

The NewtonTM, a two-ounce device about the size of a plump pen, is also sturdier than the TonopenTM, Feldon says.

Later this month doctors at the Doheny Eye Institute at the University of Southern California will begin testing the NewtonTM on patients, comparing the device to more established technologies. Heavy scrutiny by doctors is standard for any new medical device; the TonopenTM, for instance, has been tested in more than 40 clinical trials.

Feldon's company, Eye-Deas LLC of California, has just built the first NewtonsTM. The device has been approved by the Food and Drug Administration, and Marco Ophthalmics of Florida has licensed the technology.

About 3 million Americans have glaucoma, according to the Glaucoma Research Foundation. It's the second leading cause of blindness in the United States and occurs mainly as people age. The disease is much more common among African-Americans, who are about 15 times more likely than Caucasians to go blind from glaucoma between the ages of 45 and 65.

Detecting the disease is the reason behind some common but seemingly peculiar tests at the eye doctor's office. Doctors measure the pressure inside the eye by temporarily flattening a tiny part of the eyeball and measuring the amount of force needed. Many patients face an abrupt puff of air that bounces off the eye. Others receive an eye drop of anesthetic before an eye expert approaches and appears prepared to scribble on one's eyeball – the doctor is actually touching the patient's eye with a device to measure pressure. It's a little bit like nudging a piece of Jello with a feather to test how firm the Jello is.

Feldon's roots as a tinkerer go back to the early days of computing, when as a college student in the 1960s he worked as a self-trained computer programmer, later earning spending money by computerizing research laboratories at Massachusetts General Hospital.

As a physician he has continued to tinker and invent products and now holds seven patents; by inventing instruments used around the world, he improves eye care not only for the patients he sees directly, but also for millions of patients he will never meet. The TonopenTM, for instance, made glaucoma screening possible for many people who previously had difficulty being tested – for instance, people in wheelchairs or others who had difficulty maneuvering into heavily equipped chairs in doctors' offices, or patients in clinics where only a few offices were equipped with the standard, bulky technology.

"A surprisingly number of people have difficulty maneuvering in a doctor's office," says Feldon. "With this device, the patient can really be in almost any position, and a doctor can get a good measurement quickly. All patients should have access to this technology, which can detect glaucoma early and perhaps save their sight."

Feldon, who specializes in neuro-ophthalmology, is listed in Best Doctors in America. He is also professor of Ophthalmology, Neurology, Neurosurgery, and Visual Sciences.