For people living with aniridia-related keratopathy (ARK), progressive damage to the eye’s surface can cloud the cornea, impair vision and, in severe cases, lead to profound sight loss. Now, researchers at Moorfields Eye Hospital and University College London (UCL) have reported encouraging results from the first human trial of a novel stem cell treatment designed to repair the damaged ocular surface.
Published in JAMA Ophthalmology, the early-stage study found that a collagen stem cell scaffold improved both the health of the eye’s surface and visual function in patients with ARK, a rare genetic eye disorder that has previously had limited treatment options.
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What is aniridia-related keratopathy?
Aniridia is a rare eye disorder that affects normal eye development and is commonly linked to inherited genetic abnormalities. One of its serious complications is aniridia-related keratopathy, or ARK.
ARK is associated with mutations in the PAX6 gene and affects an estimated one in 40,000 to one in 100,000 people. The condition involves a shortage or dysfunction of limbal stem cells – specialised cells located at the border between the cornea and the sclera, or white part of the eye. These cells normally help maintain and regenerate the corneal surface. When they are deficient, conjunctival tissue can grow over the cornea. This can make the normally transparent cornea increasingly opaque and irregular, progressively reducing vision.
How does the stem cell scaffold work?
Researchers developed a collagen scaffold designed to deliver two types of stem cells directly to the damaged ocular surface: limbal epithelial stem cells and stromal stem cells.
Nine people with ARK received the treatment in one eye, while their untreated eye served as a control. The researchers then monitored changes in the condition of the ocular surface and visual acuity. The results were promising. Before treatment, the average ocular surface score (OSS) was 9.4 in treated eyes. After three months, it fell to 5.9, indicating improvement, and remained better at 6.7 after 12 months. By comparison, untreated eyes showed little improvement, with the average score reaching 8.0 after a year.
Vision improved by nearly five lines
The study also reported a meaningful improvement in visual function. Participants experienced an average increase of 24 letters on the ETDRS vision test, equivalent to almost five lines on a standard eye chart. While the findings are encouraging, the trial involved only nine patients, meaning larger studies are needed to determine how effective and safe the treatment is over the long term.
Professor Sajjad Ahmad of Moorfields Eye Hospital and UCL described the approach as the first optical use of a collagen scaffold containing two types of stem cells. Researchers now plan to advance the treatment into a larger clinical trial, with the longer-term goal of potentially making it available through the NHS.
A potential new treatment for corneal damage
The findings offer hope for people with ARK, limbal stem cell deficiency and progressive corneal damage. Rather than simply managing symptoms, the approach aims to restore the cells needed to maintain a healthy eye surface.
Although more research is required before the treatment could become widely available, this first-in-human trial represents an important step forward in stem cell therapy for eye diseases and could open new possibilities for treating previously difficult-to-manage causes of vision loss.