A dual stem cell scaffold improved vision and eye surface scores in a small first-in-human trial for aniridia-related keratopathy.
For people with ARK (aniridia-related keratopathy), progressive damage to the eye’s surface can gradually cloud the cornea and severely reduce vision. In a first-in-human clinical trial at Moorfields Eye Hospital and University College London (UCL), a stem cell treatment improved vision in patients with this previously untreatable rare genetic condition. The findings were published in JAMA Ophthalmology.
Aniridia is an eye surface disorder involving limbal stem cells, which are located at the boundary between the sclera (white of the eye) and cornea (the clear area at the front of the eye). Usually caused by an inherited genetic abnormality affecting eye development, the condition can result in profound vision loss.
ARK is a progressive form of aniridia caused by a mutation in the PAX6 gene and affects between one in 40,000 and one in 100,000 people. A shortage of limbal stem cells allows conjunctival tissue to spread across the cornea, making it opaque and creating a thickening layer that progressively impairs vision.
Researchers at Moorfields and UCL developed a collagen scaffold engineered to deliver two kinds of stem cells, limbal epithelial stem cells and stromal stem cells, directly to the affected area. Each of the nine participants received the treatment in one eye, while the untreated eye served as a control.
Treated eyes showed measurable improvement
At the beginning of the trial, the nine patients had an average OSS (ocular surface score, to assess the state of the eye’s surface) of 9.4 in treated eyes and 8.4 in untreated eyes. (Scores of 0-5 are classified as mild, 6-10 moderate, and 11-15 severe). The average score in treated eyes improved to 5.9 after three months and was 6.7 after twelve months, while untreated eyes changed little, reaching 8.0 after twelve months.
Vision also improved. Scores on the ETDRS (early treatment diabetic retinopathy study) vision test increased by an average of 24 letters, equivalent to nearly five lines on a standard vision chart.
Professor Sajjad Ahmad, consultant ophthalmic surgeon at Moorfields Eye Hospital and professor of corneal regeneration at the UCL Institute of Ophthalmology, said: “This is the first-ever optical use of a collagen scaffold containing two types of stem cells and has proved effective for a previously untreatable progressive condition leading to sight loss. We are now looking to take this forward to a larger clinical trial, with a view to this being accepted as an NHS treatment.”
Reference: “Combined Limbal Epithelial and Stromal Cell Transplant for Aniridia-Related Keratopathy: A Nonrandomized Clinical Trial” by Abigail Eve Kaye, Louise Morgan, Radhika Shah, Amanda J. Vernon, Andrew Embleton-Thirsk, Hakim-Moulay Dehbi, Daniel Sibley, Ahmed Oreaba, Julie T. Daniels and Sajjad Ahmad, 23 July 2026, JAMA Ophthalmology.
DOI: 10.1001/jamaophthalmol.2026.2701
This research was made possible by funding from Medical Research Council, Moorfields Eye Charity and the NIHR Biomedical Research.
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