A hospital said Thursday it has performed the world's first clinical trial of a transplant of photoreceptor cells derived from induced pluripotent stem cells, or iPS cells, to treat a patient with pigmentary retinal degeneration.

Kobe City Eye Hospital in Hyogo Prefecture conducted the clinical trial on a patient with the disease, which can cause vision problems including trouble seeing at night due to a progressive loss of photoreceptor cells in the retina.

There are some 30,000 sufferers of the genetic disorder in Japan, and there is no known treatment.

Depending on how far the disease has progressed, a patient's vision may not improve significantly. Still, the research team aims to verify its safety on humans after it completed testing of the iPS cells on animals.

As gene mutations are believed to be the cause of pigmentary retinal degeneration, the team used iPS cells grown from the blood cells of a healthy donor rather than those of the patient.

The cells were cultured into three-dimensional retinal tissue using various substances, which was then made into a sheet containing photoreceptor cells and transplanted into the patient's retina.

The patient will be observed for a year to see that the body does not reject the transplanted cells. The research team will also investigate whether the new cells communicate vision with existing cells in the body and transmit information to the brain.

The team plans to perform a clinical trial of the procedure on a second patient.

The iPS cells, developed by Kyoto University's Shinya Yamanaka who won the 2012 Nobel Prize in physiology or medicine for the achievement, can grow into any type of body tissue.

The world's first clinical test using iPS cells was conducted in 2014 by government-backed research institute Riken, transplanting retina cells into an individual with a different eye disease.