Optical Conclusions : ‘EyeDentifying’ System Is Faster Than Fingerprints

Suspects booked into the Dade County Jail answer the required questions, press their inked fingers on paper and then look, one eye at a time, into a small box mounted on the wall.

The equipment in that box offers the fastest and most reliable method of positive identification developed yet: an electronic picture of the blood vessels at the back of the eye.

Because each retina boasts a unique pattern that is first recorded with an infrared scan and then stored in a computer, the procedure is virtually foolproof.

“You can’t fool Mother Nature,” said John Harvey, a consultant for EyeDentify Inc., the Beaverton, Ore., company that developed and markets the technology. Harvey specializes in developing the computer programs for use in jails.

Two of the boxes, called EyeDentification System 7.5 and known informally as EyeDentifiers, are installed at the jail. The Dade County Corrections Department eventually hopes to place 38 throughout the jail at an estimated cost of $440,000, said Capt. Kevin Hickey, the department’s deputy director.

Largest User to Date

The Dade County Corrections Department, larger than systems in 26 states, is the first and biggest to use the technology. EyeDentifiers are also in place in Brevard County, Fla., and Lavoylles Parish, La. The system is being tested at Leiber Correctional Institution in Ridgeville, S.C.

Inmates are curious about the equipment, tucked in beside the telephones, said Officer Leon Lewis, who is responsible for taking the readings.

“They want to try. Even guys that have been here before, they want to try,” Lewis said. “It’s more like a Space Age thing to them: Modern technology, here we go again.”

The EyeDentify technology, which was installed permanently at the beginning of the year following a nine-month pilot program, is already used to make sure the right prisoner is released from the jail, into which between 110,000 and 115,000 people are booked a year.

“I’d spend $440,000 on that alone,” Hickey said.

About once or twice a year, the wrong inmate goes free, Hickey said.

“Sitting in the holding cells, one guy buys another off,” he said.

Series of Questions

Prisoners being released from the jail are only asked a series of questions, such as their Social Security number and mother’s maiden name. Fingerprint identification can take four hours or more in areas where files extend into the hundreds of thousands, so it is not used. In many cases, an expert’s visual confirmation is needed.

The EyeDentifier also spots habitual offenders in under one minute, regardless of the name they give. About 65% of the people booked into the jail are arrested after their release, Hickey said.

When all the EyeDentifiers are in place, they will be able to track prisoners as they move from one area of the 25-year-old jail to another.

Scientists have known since 1935 that the pattern of blood vessels at the back of each eye is unique. But it took Robert (Buzz) Hill, an electronics engineer, and his father, Dr. Robert Hill, an ophthalmologist, about eight years, starting in 1975, to combine various optical and electronics techniques that record and store the pattern.

Identified at 320 Points

An infrared scan passes over a small circular area at the back of the eye, determining the location and distribution of the deeper blood vessels in the retina. About 30 to 40 of the larger blood vessels, measuring from 100 microns (one-millionth of a meter) to 250 microns, are identified through readings at 320 points.

As darker colors, in this case the blood vessels, absorb light and brighter colors reflect it, the amount of light returned from the retina gives the pattern.

Light detector photo cells in the EyeDentifier respond proportionately to the intensity of the light that comes back and it is transformed into an electric current. That current is then converted into digital impulses so it can be stored in the computer.

Looking into the EyeDentifier, the viewer lines up a series of yellow dots that appear suspended in space. Enrolling does not hurt and bloodshot eyes make no difference in the recorded pattern.

There is no danger to the eye, Harvey said, comparing the amount of light exposure to opening the refrigerator to get a can of beer.

The computer gives an accuracy reading, foiling any attempts to avoid enrollment.

Once recorded in the system, a person simply looks into the lens and the computer compares the retinal pattern with a stored template.

The EyeDentify system is used by firms to control access to restricted areas and to monitor employee attendance. It is in place, for example, at Sandia Labs in Albuquerque, N.M., and in the mail room at the Arkansas Democrat in Little Rock, said Gretchen Luder, administrator of sales for EyeDentify.

“Susie can’t punch Tom in when he’s late,” she said.