They formulated the drug Ataluren into eye drops, and found that it consistently restored normal vision in mice who had aniridia (ANN-uh-ridee- uh), a condition that severely limits the vision of about 5,000 people in North America. A small clinical trial with children and teens is expected to begin next year in Vancouver, the U.S. and the U.K.

Aniridia is caused by the presence of a "nonsense mutation" - an extra "stop sign" on the gene that interrupts production of a protein crucial for eye development. Aniridia patients don't have an iris (the coloured ring around the pupil), and suffer many other eye abnormalities.