In a report published in the academic journal Ophthalmology researchers revealed they’ve identified a new layer of tissue in the human cornea. Named Dua’s layer, after Professor Harminder Dua from the University of Nottingham in the U.K. who discovered it, the previously undetected sixth layer of the cornea located towards the back of cornea, between the corneal stroma and the Descemet’s membrane. While the entire cornea is around 550 microns thick (0.5mm), the new layer is just around 15 microns thick and has proved to be incredibly strong and tough.
Dr. Dua and his group were conducting transplant-related research on donated eyes. Simulating corneal surgery, they injected tiny bubbles of air into the cornea. Descemet’s membrane was surgically removed, causing the air bubble to dissipate in some specimens (“type II bubbles”), but not others (“type I bubbles”). Further experimentation revealed that all air-bubble-free specimens could be re-inflated with a type I bubble. After the bubble was inflated to the point of popping, no further bubble could be formed from further injection, indicating that the bubble was being trapped by a distinct layer of material, not a random variation in the corneal stroma.
The experimental results were confirmed via electron microscopy. The microscope showed a thin layer of corneal collagen between the corneal stroma and Descemet’s membrane.
“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,” Dua explains.
The find was first described in the journal Ophthalmology in May 2013