Dua for the Price of One

Last year, a new  layer of the cornea was described by Harminder Dua and colleagues at Nottingham University, UK. Comprised of thin collagen plates, “Dua’s layer” is just fifteen microns thick yet it is incredibly tough. The finding had implications for corneal surgery and the understanding of corneal diseases (1). At the time, we asked the eminent professor, “Do you think we now know the complete anatomy of the eye, or is there more to be discovered?” His reply was, “Well, as a follow-up to this paper, we will be introducing another little surprise.”

We know have that “little surprise”. Using electron microscopy on human donor eyes, the Nottingham team examined Dua’s Layer at the extreme periphery of the cornea. There, they discovered, the collagen fibers of the layer branch out to form a meshwork. The core of the trabecular meshwork is in fact an extension of Dua’s Layer (2).

“Many surgeons who perform lamellar corneal transplant recognize this layer as an important part of the surgical anatomy of the cornea,” Dua says. “This new finding resulting from a study of the microanatomy of the periphery of the layer could have significance beyond corneal surgery.”

It certainly opens up a new avenue of research into glaucoma, where it may offer new clues as to why the trabecular meshwork malfunctions in this sight-robbing disease. Moorfield-based David Garway-Heath, the International Glaucoma Association Professor of Ophthalmology said of the discovery, “Trabecular meshwork dysfunction that results in impaired outflow of aqueous humor is the main cause of raised IOP in glaucoma. Knowledge of the anatomical origin and organization of the trabecular meshwork will aid our understanding of its function and may stimulate new research into modulating trabecular meshwork  function which, in turn, could lead to new therapies”.