The U.S. Food and Drug Administration (FDA) has approved of the first gene therapy designed to treat an inherited vision loss disease that typically results in blindness.

The gene therapy, called Luxturna, will now be able to treat patients with hereditary retinal dystrophy — a rare condition wherein a mutation in one's RPE65 gene destroys the cells that are essential for healthy vision.

Those affected by the genetic disorder experience loss of vision during childhood or adolescence and the condition eventually progresses to complete blindness.

"Today's approval marks another first in the field of gene therapy—both in how the therapy works and in expanding the use of gene therapy beyond the treatment cancer to the treatment of vision loss—and this milestone reinforces the potential of this breakthrough approach in treating a wide range of challenging diseases," FDA Commissioner Scott Gottlieb, M.D. said on Tuesday, Dec. 19.

Luxturna works by delivering a normal copy of the RPE65 gene directly to one's retinal cells. These cells will then be able to produce the correct protein that converts light into an electrical signal. This process leads to the restoration of vision loss for patents.

In the clinical trials, 41 patients with ages ranging from 4 to 44, all of whom were confirmed to have biallelic RPE65 mutations, were administered Luxturna. On a Phase 3 study with 31 participants, the gene therapy was observed to have resulted in significant improvements.

As a form of treatment, Luxturna is meant for patients who still have viable retinal cells. The gene therapy is administered via subretinal injection, with the process being done on each eye on separate days. There should be at least six days in between the surgical procedures.

Gene therapy has also shown promising results in treating many other conditions such as leukemia and lymphoma. However, one downside is that treatment is very expensive.

Spark Therapeutics has not released pricing but Luxturna is expected to cost at least $1 million per patient. Patients' safety should also be considered as some adverse reactions from Luxturna include eye redness, cataract, retinal tear and increased intraocular pressure.