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P&S Journal

P&S Journal: Spring 1995, Vol.15, No.2
P&S News
Space Visual Sciences Center Proposed

Scientists at the Edward S. Harkness Eye Institute have made NASA officials an unprecedented offer to track the long-term visual health of its astronaut corps in return for NASA's support of a Visual Sciences Center at Columbia. Dr. Basil Worgul, professor of radiation biology in ophthalmology, says the project marks one giant leap for both the University and NASA.

"Historically, the medical care of astronauts has been the domain of the Johnson Space Center and will remain so," Dr. Worgul says. "We want to take it one step further. We want to study the eye not only to examine it from a medical point of view but because of its importance to the success of a mission."

The eye contains cells and tissues that resemble other vital body systems, making this "window to the world" a practical "window to within," Dr. Worgul says. The center's scientists would track the eye health of the existing astronaut corps through non-invasive clinical exams and highly specialized imaging procedures during the next two decades of space activities in low earth orbit (LEO). Such a long-term, non-invasive follow-up would enable scientists to predict how the visual system will respond to deep space travel.

"We don't anticipate seeing clinical changes from LEO activities because they're going to be relatively short-term at each interval, maybe 30 to 90 days a year," Dr. Worgul says. "But we feel that with our equipment we would be able to detect sub-clinical changes with a high degree of resolution, which can give us a certain amount of insight into the probable influence of more extended space travel. At the very least, the opportunity to extensively analyze what amounts to a physiologically elite group could also give us an opportunity to rewrite a lot of ophthalmology books."

The effects of ions on the visual system in space became known when the crew members of Apollo 11 reported seeing light flashes, streaks, and "star bursts" during their mission. "What these turned out to be were heavy ions in the cosmic radiation flux coming through the ship, through their heads, through their retinas and in many cases out the other side of the ship," Dr. Worgul says. "We have shown that they probably did not cause ocular damage during their traverses, but they did cause visual responses by ionization. The retina certainly did not suffer a hole for each traverse as some people were predicting, which is good. An average 10-day lunar trip, in and out, generated about 1,200 hits per square centimeter of astronaut."

Still, while NASA officials blueprint missions to Mars and beyond, no one knows for sure how the visual system will react in a deep space environment. "There are predictions of various sorts that astronauts on the way to Mars in a three-year scenario-one year out, one year there, and one year back-will be exposed to heavy ions from cosmic radiations," Dr. Worgul says. "At least one theory holds that about 30 percent of all the nuclei of all the cells of their bodies will be traversed by particles depositing energies exceeding 100,000 electron volts for each micron traveled."

Dr. Worgul expects NASA to respond to the offer within a year. Meanwhile, he considers the proposed center a unique opportunity for both parties. "We have an outstanding faculty in the eye field so interested in the nature of this study that they're willing to examine astronauts over the course of their active lifetimes for no compensation. We also have a number of laboratories which have generated prototypic equipment for quantitative assessment of the human eye, copies of which exist very sparsely throughout the world. By intensively examining such a population and having the appropriate controls, we could provide a greater understanding of the visual system while compiling experience extending across different populations and different ages."

copyright ©, Columbia-Presbyterian Medical Center

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