They suffered from macular degeneration.
Three women in Florida were left blind after receiving treatment using stem cells, NPR reports.
The women, who were in their 70s and 80s, had the injections as a therapy for macular degeneration. Their cases were recently detailed in an article in the New England Journal of Medicine.
They received the treatment at a for-profit clinic. The adult stem cells were derived from fat tissue.
The patients paid $5,000 each for the treatments.
NPR reports that the NEJM article "is renewing calls for the Food and Drug Administration to crack down on the hundreds of clinics that are selling unproven stem cell treatments for a wide variety of medical conditions, including arthritis, autism and stroke."
NPR notes that the clinic was not named in the NEJM report. However, on a government site, "The sponsor is listed as Bioheart, Inc., which is part of U.S. Stem Cell Inc. in Sunrise, Fla.," according to the news site.
Kristen Comella, U.S. Stem Cell's scientific director, wouldn't comment specifically on the three women's cases, but told NPR: "We feel very confident about the procedures that we do, and we've had great success in many different indications."
Read more at NPR