Synthetic corneas restore sight: Swedish study

A Swedish study has revealed that biosynthetic corneas can help regenerate and repair damaged eye tissue and improve vision in humans, the Science Translational Medicine reported last week.

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The results, from an early phase clinical trial with 10 patients, were reported in the publication on Wednesday.

"We are very encouraged by these results and by the great potential of biosynthetic corneas," said Linköping University eye surgeon Dr. Per Fagerholm.

"Further biomaterial enhancements and modifications to the surgical technique are ongoing and new studies are being planned that will extend the use of the biosynthetic cornea to a wider range of sight-threatening conditions requiring transplantation," he added.

Dr. Fagerholm's collaboration with senior author Dr. May Griffith of the Ottawa Hospital Research Institute, the University of Ottawa and Linköping University has resulted in the first human experience with biosynthetic cornea implantation.

"This study is important because it is the first to show that an artificially fabricated cornea can integrate with the human eye and stimulate regeneration," said Dr. Griffith.

"With further research, this approach could help restore sight to millions of people who are waiting for a donated human cornea for transplantation," she added.

The cornea is a thin transparent layer of collagen and cells that acts as a window into the eyeball. It must be completely transparent to allow the light to enter and it also helps with focus.

Diseases resulting in corneal clouding are the most common cause of blindness.

Dr. Griffith and her colleagues began developing biosynthetic corneas in Ottawa more than 10 years ago using collagen produced in laboratories and moulding them into corneas. They initiated a clinical trial with 10 Swedish patients with advanced keratoconus or central corneal scarring

Each patient underwent surgery on one eye to remove damaged corneal tissue and replace it with the biosynthetic cornea, made from synthetically cross-linked recombinant human collagen.

Over two years of follow-up, the researchers observed that cells and nerves from the patients' own corneas had grown into the implant, resulting in a "regenerated" cornea that resembled normal healthy tissue.

Patients did not experience any rejection reaction or require long-term immune suppression, serious side effects associated with the use of human donor tissue.

The biosynthetic corneas also became sensitive to touch and began producing normal tears to keep the eye oxygenated.

Vision improved in six of the 10 patients and after contact lens fitting, vision was comparable to conventional corneal transplantation with human donor tissue.