WIKIMEDIA, PETR NOVAK
At a mere 15 microns thick, an incredibly strong layer has been discovered sandwiched within the human cornea. The new layer is called Dua’s layer, after its discoverer Harminder Dua, an ophthalmologist at the University of Nottingham. Dua and his team published their findings in the journal Ophthalmology.
Previously, the human cornea, which is approximately 550 microns thick, was thought to be comprised of five layers: from front to back, the corneal epithelium, Bowman’s layer, the corneal stroma, Descemet’s membrane, and the corneal endothelium. Based on clinical experience with corneal transplants, Dua suspected a layer existed between the corneal stroma and Descemet’s membrane. To prove the existence of this layer, Dua’s team carried simulated corneal transplantations on several donated human eyes. These surgeries typically involve first separating corneal layers by pumping small air bubbles in between them and then removing and replacing the diseased layer. By injecting even smaller bubbles, the scientists were able to reveal the new Dua’s layer, whose unique structure they confirmed with electron microscopy.
The discovery may bring about improved outcomes for patients undergoing corneal grafts and transplants. Because Dua’s layer, composed primarily of collagen, is so strong, surgeons performing certain types of corneal surgeries could plan to inject air closer to this layer, rather than near more fragile layers that are more prone to tearing.
The discovery could also advance the understanding and treatment of several cornea diseases, including acute hydrops, Descematocele, and pre-Descemet’s dystrophies.
“This is a major discovery that will mean that ophthalmology textbooks will literally need to be re-written,” said Dua in a statement. “Having identified this new and distinct layer deep in the tissue of the cornea, we can now exploit its presence to make operations much safer and simpler for patients. From a clinical perspective, there are many diseases that affect the back of the cornea which clinicians across the world are already beginning to relate to the presence, absence or tear in this layer.”