New layer of human cornea discovered

Research at University of Nottingham has uncovered a previously undetected layer in the cornea, the clear window at the front of the human eye.

Detailed in Ophthalmology, the breakthrough could help surgeons dramatically improve outcomes for patients undergoing corneal grafts and transplants.

“This is a major discovery that will mean that ophthalmology textbooks will literally need to be rewritten,” said Professor Harminder Dua who made the discovery which has now been dubbed ‘Dua’s Layer’.

The cornea is the eye’s transparent, protective lens through which light enters. It was previously assumed that the structure consisted of just five layers: the corneal epithelium, Bowman’s layer, the corneal stroma, Descemet’s membrane and the corneal endothelium.

The newly discovered layer is located at the back of the cornea between the corneal stroma and Descemet’s membrane. It’s just 15 microns thick, but is incredibly tough – strong enough to be able to withstand two bars of pressure.

Dua and his team demonstrated the existence of the new layer by stimulating human corneal transplants and grafts on eyes donated for research to eye banks in Bristol and Manchester.

During the surgery, the layers were separated by injecting tiny bubbles of air into the cornea. The researchers then applied electron microscopy to study the separated layers.

Further study of the Dua’s layer could one day help surgeons to better identify where in the cornea these bubbles are occurring, so they can take appropriate measures during the operation. The Dua layer is less prone to tearing due to its toughness so it’s an ideal place to inject a bubble.

“Having identified this new and distinct layer deep in the tissue of the cornea, we can now exploit its presence to make operations much simpler and safer for patients,” conclude Dua.

Paper: Human Corneal Anatomy Redefined : A Novel Pre-Descemet's Layer (Dua's Layer)