The Light Goes On

Medical school dean leads innovations that advance diagnosis and treatment of common causes of blindness.

By Ina Fried and Veronica Jauriqui
Summer 2008

Millions of people around the world may avoid blindness from retinal diseases thanks to two innovations—one a diagnostic technology and the other a new use of a medication. Both were pioneered by the new dean of the Keck School of Medicine of USC, Carmen A. Puliafito, M.D., M.B.A.

High-Resolution Diagnosis Named by Ocular Surgery News as one of the top 10 innovations over the past 25 years, optical coherence tomography (OCT) is “an imaging technology for looking at the retina in the living human eye that provides a non-invasive anatomical cross section of the macula,” says Puliafito. Located at the back of the eye, the retina is the ultra-thin layer of cells that collect light; the macula is the retina’s central part that allows the eye to see fine details at the center of the field of vision.

Puliafito led a team at Harvard University Medical School—where he founded the Laser Research Laboratory in the Department of Ophthalmology—in inventing and developing OCT. Collaborators from the Massachusetts Institute of Technology included David Huang, M.D., Ph.D., now director of the Doheny Laser Vision Center and holder of the Manger Chair in Corneal Laser Surgery at the Keck School.

“We built the first machine in the world in 1994,” Puliafito says. “We did the first human studies, and now there are 9,000 machines all over the world. We were involved in the development , as well as the commercialization, of the technology.”

OCT measures light as it is reflected across a solid object through a rapid sequence of a thousand or so separate scans. The images are then combined to create a two-dimensional, cross-sectional picture of the object. Because it relies on light rather than sound or radio waves, OCT can provide resolution up to 100 times finer than with other imaging methods.

Prior to OCT, most retinal exams involved dilating the pupil and taking a look inside. Usually done with a microscope, the exam could detect swellings, holes or cysts, but at a low resolution.

The high-resolution images of OCT have revolutionized clinical diagnostics in ophthalmology. OCT has become critically important for early detection of serious eye diseases that originate within the retina.

According to the National Institutes of Health, the leading causes of blindness in the United States are diabetes, glaucoma and macular degeneration. All three can be imaged using OCT, says Puliafito, who sees patients at USC Doheny Eye Institute on the USC Health Sciences Campus in East Los Angeles.

A thinning of the retinal tissue is an indication of glaucoma; a swelling suggests diabetic retinopathy. OCT can detect these subtle abnormalities much sooner and speed treatment to hold blindness at bay.

Innovative Treatment The second innovation in the prevention of blindness from retinal diseases is the injection of Avastin ™—an anti-cancer drug—into the eyes of patients with macular degeneration. Puliafito pioneered this research while he was director of the Bascom Palmer Eye Institute and chair of the Department of Ophthalmology of the University of Miami Miller School of Medicine. He came to Los Angeles from Miami in November.

In the Western world, age-related macular degeneration is the leading cause of legal, irreversible blindness among people 50 years of age and older. It is expected to affect nearly three million people in the United States by 2020. So-called “dry” macular degeneration progresses slowly to cause loss of central vision. Central vision is sometimes destroyed suddenly in “wet” macular degeneration, caused by blood vessels growing in the macula and leaking fluid and blood.

Avastin, a drug designed to inhibit the growth of abnormal blood vessels, has been shown to substantially reduce the leakage from abnormal blood vessels in the eyes of patients with wet age-related macular degeneration. Eyes treated with Avastin were reported to have improved vision in as little as one week.

To make an appointment at the Doheny Eye Institute, call 800-USC-CARE or 323-442-6335.

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