Tomorrow's Health, Today's Research

Dr. Robert Chow

Assistant Professor, Biology Department
Canada Research Chair in Retinal and Early Eye Development
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Phone: (250) 472-5658
Department Page
Research area: retinal development and hereditary vision defects
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Research Profile:

Regulating vision: the puzzle of Vsx1

How the body grows with the right symmetry is a deeply mysterious process, highlighted by the bizarre results when things go wrong. Take microphthalmia, a condition that gives children abnormally small eyes. In a related condition, anophthalmia, children are missing one or both eyes, leaving empty sockets. In both situations, the children can be fitted with prosthetic eyeballs for a cosmetic solution; however they remain blind in the affected eye.

Dr. Robert Chow is fascinated by developmental biology in general and has focused on the eye for his research. He began his career by discovering a “master regulatory” gene for eye formation. Chow made the remarkable observation that this gene, called Pax6, had the ability to generate third, fourth and even fifth eyes in tadpoles.

After working at Toronto’s Hospital for Sick Children, Chow came to UVic in 2004 and became the Canada Research Chair in Retinal and Early Eye Development. The retina is a thin layer of neural cells that lines the back surface of the inside of the eye. It is where light is detected and transformed into a chemical signal that is sent to the brain. As neural cells go, retinal cells are relatively simple, yet despite their simplicity, the retina has an enormously wide range of cell types. Chow is interested in how these different cells types develop from retinal stem cells.

Chow’s current work stems from a discovery made by colleagues at the Hospital for Sick Children.They discovered that microphthalmia (a blinding condition that results in the formation of tiny non-functional eyes) is caused by mutations in a gene called Chx10. They showed that Chx10 controls retinal development, and if the retina develops poorly, so does the rest of the eye. Chow decided to work on a related gene , theorizing that Vsx1 has enough DNA sequence similarity to Chx10 to have a similar role in retinal development.

While it’s become clear that Vsx1 is involved in retinal development, its role seems different from Chx10. For instance, Chow observed that the absence of Vsx1 does not lead to anophthalmia. However, Chow found that Vsx1 controls the formation of a type of retinal cells called bipolar cells, which sit between photoreceptors and the optic nerve. Without Vsx1, some bipolar cells do not mature properly. There are about 10 types of bipolar cells, and these modify and refine visual information as it makes its way to the brain.

What his observations mean with respect to human vision is something that Chow, his students and research associates at UVic are trying to figure out. As bipolar cells are functionally diverse, if something goes wrong with their development, or if a few of these cells development incorrectly, a person can potentially end up a variety of different visual defects. Chow notes that Vsx1 functions in only a small subset of bipolar cells, and therefore the overall effect on vision in the absence Vsx1 might be subtle.

Adding to the puzzle, Vsx1 may have a role in eye tissues outside of the retina. Some people with mutations in Vsx1 also have cornea dystrophy. However, there is controversy as to whether these mutations are actually responsible for this type of disease. Chow’s lab is directly addressing this controversy by developing genetic models to re-create and examine the human Vsx1 mutations. Determining whether the human Vsx1 mutations are responsible for corneal disease could lead to the development of approaches to cure or prevent these diseases.