A woman in her 70s being treated for an eye disease is making good progress a year after she underwent the world's first transplant using iPS-derived cells, a team of researchers said Friday.

The team, comprising members from the Riken institute and the Institute of Biomedical Research and Innovation Hospital, successfully transplanted retinal cells grown from induced pluripotent stem cells to the woman.

If the operation is deemed safe, it could boost the use of iPS cells, which can grow into various human tissues, in treating ailments such as Parkinson's disease, Alzheimer's and other illnesses.

At a news conference in Kobe on Friday, team members said that since the surgery in September last year, the woman has had no complications and no confirmed abnormalities, including cancer.

The woman suffered from wet-type age-related macular degeneration, a disease that can lead to distorted vision, seeing dark spots and even the loss of sight. About 700,000 people are believed to suffer from the illness in Japan.

The team said the patient's vision has stopped deteriorating. She was quoted as saying, "I am glad I received the treatment. I feel my eyesight has brightened and widened."

Masayo Takahashi, a Riken researcher and member of the team, said, "I hope we can make this a standard treatment soon."

The team had planned to conduct a second transplant of retina cells produced from iPS cells, but cancelled it after finding genetic mutations in the iPS cells.