Out cell

A surgery transplanting just one layer of the cornea is able to improve the sight of patients with keratoconus and delay the need for a full corneal transplant, a pioneering trial has demonstrated.

Seeking an alternative to the therapies available for keratoconus, Netherlands Institute for Innovative Ocular Surgery (NIIOS) researchers have transplanted the Bowman layer from donor tissue to the eyes of 19 patients with the incurable disease, whose eyes were unsuitable for corneal cross-linking.

The Bowman layer is the second layer of the cornea, and contains no cells. This makes it well suited for transplantation, as cells can trigger an immune response in the recipient and organ rejection.

In the stitch-free procedure, the Bowman layer is placed in the middle layer of the cornea using a tiny tube, promoting the eye’s healing response and strengthening and flattening the cornea. The surgery carries less risk than a full replacement, and allows patients to use contact lenses to correct their vision for a longer period.

Of the surgeries performed on the 19 patients, the progression of the disease was halted in every case but one, explained the research team presenting at AAO 2016 (14–18 October, Chicago).

In the five years since, no patient experienced post-surgery complications and the patients’ corrected vision improved from 6/120 to 6/60, highlighted NIIOS corneal researcher, Jack Parker.

None of the patients experienced persistent astigmatism either, a common complication with full corneal transplants.

Mr Parker emphasised that: “Bowman layer transplantation may be safer than a full corneal transplant, is effective and the benefits last. The procedure can spare young people with the condition a lifetime of difficult, expensive and risky eye procedures and interventions.”

Mr Parker explained that a larger study evaluating the technique was the next step for the research.

Image credit: Tim Samoff