Tuesday, March 23, 2010

Saving Premature Babies' Eyesight

Dr Arnall Patz, an ophthalmologist who discovered and eliminated a major cause of blindness in premature infants -- passed away from heart disease on March 11. He was 89.

In 1954, Patz proved that treating premature babies with pure oxygen could destroy their eyesight. At the time, this was the most common cause of blindness in premature infants.

As was a young physician at Washington DC's Gallinger Municipal Hospital (now known as DC General Hospital), Patz observed that a new incubator, sealed all around to contain an inner climate, was enabling doctors to save premature babies. "But something was wrong," he told the Baltimore Sun in 2004 profile. Patz noticed that the advance coincided with an epidemic of infant blindness, and that most of the victims were "preemies" who lay for weeks in an atmosphere of near-total oxygen.

"In a question that outraged physicians at the time, but later won their admiration, Dr Patz wondered whether there might be a connection: Was it possible that oxygen was robbing babies of their sight?" the profile read. "It had become standard practice to put babies in incubators and crank up the oxygen," Patz told the Sun. "[I] could hardly blame the doctors who did this because it turned struggling babies from blue to pink."

Unable to secure grant money to prove their hypothesis, Patz and his colleague Leroy Hoeck funded their early tests with money borrowed from Patz's brother Louis, later receiving a small grant after promising to turn on the oxygen at the first sign of troubled breathing.

Their hunch was correct: Almost immediately, doctors stopped automatically giving oxygen to premature infants, ending the epidemic of blindness because of retrolental fibroplasias, now known as retinopathy of prematurity (ROP). By the time the practice of providing pure oxygen to premature infants was stopped, more than 10,000 of these babies had had their eyesight destroyed.

To prove their theory, the pair of doctors conducted what is widely believed to be the first randomized controlled trial in ophthalmology. In the early 1950s, they divided 120 premature babies at Gallinger into two groups. In the first group, which received concentrated oxygen constantly, 12 infants went blind. In the second group, babies received oxygen only if they were in respiratory distress, and only one became blind.

Elevated oxygen levels, it turned out, destroyed the arteries of the eye. That in turn caused abnormally wild growth of blood vessels, irreversibly damaging the retina. It was discovered that oxygen caused blood vessels in the back of the eye to constrict. In a doomed attempt to compensate, the eye sprouted twisted vessels that would eventually bleed and destroy the retina.

"Never in the history of ophthalmology has a blinding condition become so quickly widespread and equally rapidly been abolished," wrote Scottish ophthalmologist Sir Stewart Duke-Elder in the 1970s.

The results of a subsequent larger trial led by biochemist Everett Kinsey and involving patients at 18 hospitals substantiated the earlier findings at Gallinger. Although the new understanding came too late for thousands of people who were made blind by oxygen -- including the singer Stevie Wonder.

Patz operated a ham radio from his home on behalf of the Maryland Eye Bank. According to The Wall Street Journal, Patz erected an 80 foot tower at his home and became known to amateurs across the country for putting out the word on the airwaves whenever corneas were needed for transplant.

In 2004, President George W. Bush presented Patz with the Presidential Medal of Freedom, the nation's highest civilian award, calling him "the man who has given to uncounted men, women and children the gift of sight."

- from The Wall Street Journal, The New York Times, The Washington Post and The Baltimore Sun for some information

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