A Purdue University student's research project related to zebrafish eye development could lead to a better understanding of vision problems that affect billions of people worldwide.
Zeran Li, as an undergraduate student in biological sciences, led a research team that uncovered an enzyme's role in the regulation of eye size in the fish. If the enzyme's role is similar in human eyes, it could be relevant to human vision problems, such as nearsightedness and farsightedness.
"New insights into the process of eye-size control in zebrafish may help our understanding of the regulation of eye size in humans," said Li, who has since graduated and is pursuing a doctorate in neuroscience at Washington University. "Vision problems occur when the size or shape of the eye changes, and what causes this is unclear. Perhaps this research will lead to a better understanding of this mechanism and the discovery of a new treatment for these problems."
These vision problems, called refractive errors, occur because the physical length of the eye from the cornea to the retina is different from the optical length. If an eye is too long or too short, light is focused in front of or behind the retina and vision is blurred, she said.
Refractive errors affect 3.8 billion people worldwide, according to the International Center for Eye Education.
Li worked in the laboratory of Yuk Fai Leung, a Purdue assistant professor of biological sciences. Leung oversaw the research and guided the team, but credits the two undergraduate students in his lab for the idea.
"The inspiration for this study came from the undergraduate students," he said. "Their observations and interpretations helped shape our current focus and allowed us to make this discovery. I'm very proud of the scientists they are becoming."
The findings are detailed in a paper in PLoS ONE. In addition to Li and Leung, paper co-authors include Purdue undergraduate student Devon Ptak, postdoctoral researchers Liyun Zhang and Wenxuan Zhong, and continuing lecturer Elwood Walls.
Zebrafish are used as a model to study development and growth problems. The zebrafish, which are named for their naturally occurring black stripes, must be made transparent to enable the careful observation and imaging necessary for the research. The most common way to achieve this transparency is to treat zebrafish embryos with a chemical called phenylthiourea that blocks the formation of black pigment, he said.
Li had previously observed that zebrafish embryos treated with the chemical have smaller eyes than untreated fish, and found that in addition to blocking pigmentation, the chemical inhibits thyroid activity.