On the Human Condition
Volume XXVIII Number 2
Photo © Tyagan Miller
A View to a Cure
Joseph Bonanno and his research team have staked out a tiny patch of human real estate--a whisper-thin, dime-sized layer of cells called the corneal endothelium. This structure pumps excess water from the cornea (the transparent front part of the eye) through a process known as ion transport, thus preventing swelling that can ultimately lead to irreversible sight loss and the need for a corneal transplant.
Most of Bonanno's work these days can be characterized as pure science. He and his research team members at the Indiana University School of Optometry look at cultures of corneal endothelia in the lab and document how the cells' ions--electrically charged molecules--maintain proper hydration levels within the eye.
Potential practical applications of this work, however, are never far from Bonanno's mind. Diminished function of the corneal endothelium appears to be closely tied to aging, and as the population grows older, the number of patients in need of corneal transplants will continue to outstrip the capacity of eye banks to respond.
"My focus has been on trying to understand how the endothelium works," says Bonanno, a professor of optometry. That understanding may help in the development of drug therapies to stimulate weakened endothelial cells, he says, or surgical techniques for transplanting only the back half of the cornea (where the endothelium is located), instead of the entire cornea.
Earlier periods in Bonanno's research career have led to some significant applications. While a Ph.D. student at the University of California, Berkeley, in the mid-1980s, Bonanno became interested in physiological changes caused by use of contact lenses. "The lenses were still somewhat impermeable to oxygen then," he says.
Because of that impermeability, contact lens wearers were prone to hypoxia, or oxygen deficiency. "This would cause light-scattering and degrade vision," Bonanno says. "Clinicians were concerned that it would set up a situation where the cornea would be more susceptible to infection."
Conducting tests on the pH levels in contact lens wearers' eyes, Bonanno became convinced that he needed a deeper familiarity with corneal activity at the subcellular level, which led him to a postdoctoral project at Louisiana State University on corneal ion transport.
But he has never lost his interest in contact lenses. Bonanno returned to Berkeley in 1988 to teach (he joined the IU faculty 10 years later). A graduate student in Bonanno's lab at Berkeley, Daniel Harvitt, developed a technique for noninvasively measuring oxygen levels underneath contacts. "It was something that had never been done before," Bonanno says.
After coming to Bloomington, Bonanno secured Food and Drug Administration approval to use this technique with human subjects. "Contact lens manufacturers are interested in this procedure when testing new materials," he says. "We're the only place in the world that can perform these measurements."
Because most consumers prefer soft lenses to rigid ones, much energy has gone into developing soft lenses that are as oxygen-permeable as rigid lenses. The tests in Bonanno's lab have been instrumental in that effort.
Bonanno also has been collaborating with his School of Optometry colleague P. Sarita Soni, who is co-director of the Borish Center for Ophthalmic Research (and also IU associate vice president for research). They are working on studies in orthokeratology--the use of specialized contact lenses, worn only while sleeping, that reshape the cornea and eliminate the need for daily eyewear.
Beyond the Optometry School, Bonanno recently served on a campus committee that has developed a new, interdisciplinary undergraduate program in human biology. Students in the program, Bonanno says, will consider human life in all its dimensions--from the microscopic realm that his research inhabits to large-scale concerns such as human ecology. Undergraduate vision science courses in the School of Optometry are expected to be included in the program's offerings.
Like Bonanno's own research, which balances pure and applied approaches to science, the new program, he says, "is all about the human condition."
Karen Grooms is a senior editor for the IU Office of Creative Services in Bloomington.