Patients are about to be enrolled in the first study to test a gene-editing technique known as CRISPR inside the body to try to cure an inherited form of blindness.

People with the disease have healthy eyes but lack a gene that converts light into signals to the brain that enable sight.

The experimental treatment aims to supply kids and adults with a healthy version of the gene they lack, using a tool that cuts or "edits" DNA in a specific spot. It's intended as a onetime treatment that permanently alters the person's native DNA.

Two companies, Editas Medicine and Allergan, will test this in up to 18 people around the United States, including Massachusetts Eye and Ear in Boston, starting this fall.