University of Florida scientists say they’ve delivered a gene through an eggshell to give sight to a type of chicken normally born blind.

The researchers say the study proves, in principle, a similar treatment can be developed for an incurable form of childhood blindness.

We were able to restore function to the photoreceptor cells in the retinas of an avian model of a disease that is one of the more common causes of inherited blindness in human infants, said Sue Semple-Rowland, an associate professor of neuroscience. The vision capabilities of the treated animals far exceeded our expectations.

The bird — a type of Rhode Island Red chicken — carries a genetic defect that prevents it from producing an enzyme essential for sight. The condition closely models a genetic disease in humans that causes Leber congenital amaurosis type 1, or LCA1. About 2,000 people in the United States are blind because they have a disease that falls in the LCA family.

Semple-Rowland has worked since 1986 to first discover the malfunctioning gene, known as GC1, and then to develop a viral therapy to treat it.

The research appears in the online journal Public Library of Science-Medicine,