Gene Therapy Offers Hope for Blindness
Treatment Dramatically Improves Rare, Inherited Blindness
Gene Therapy for Blindness continued...
The researchers reported a 50-fold improvement in cone function, which is responsible for color and day vision, and a startling 63,000-fold improvement in rod function, which controls night vision.
But there was a catch. While night vision did improve, it took much longer for the patients to adapt to darkness than is normal. People with normal sight adjust to darkness in an hour or less, but it took eight hours or more for the patients in the study to adjust.
"This is something that we need to try and improve as we study different vector concentrations in the future," Cideciyan says.
A patient in one of the other trials developed a small hole in the center of the retina following treatment, but the complication was believed to be the result of treatment-related surgery and not the gene therapy itself.
No major side effects were reported among the three patients in Cideciyan's trial.
Better Blindness Treatments
About 3,000 Americans have Leber congenital amaurosis, and only about 10% of these people have the RPE65 gene mutation that would make them candidates for the genetic therapy being studied.
But similar treatments could be developed to treat other inherited retinal conditions, including some forms of macular degeneration, Goldberg notes.
"The potential is tremendous, he says."
The results could even been more dramatic if the treatment is deemed safe enough for use in children with inherited retinal disease, says Stephen Rose, PhD, who is chief research officer for the Foundation Fighting Blindness.
"These studies together show the power of this treatment," he tells WebMD. "We may be able to prevent blindness in children and restore functional vision in adults who have been blind for many years."