Harminder Dua, a professor of ophthalmology and visual sciences at the University of Nottingham, has discovered a tiny, previously unknown body part hidden in the human eye. He named it after himself — Dua's layer — and detailed the revelation in the journal Ophthalmology.

Sitting at the back of the cornea — the transparent front part of the eye that helps refract light — Dua's layer is "skinny but tough," and just 15 microns thick, says LiveScience. (25,000 microns is approximately an inch.) Researchers found Dua's layer by using jets of air bubbles to gently separate the corneal layers in donated eyes, scanning each layer individually under an electron microscope.

As for what the new body part actually does, Dua believes it helps keep fluid from building up in the cornea. A tear in the layer can lead to a condition called corneal hydrops, a rare but nasty complication resulting from Keratoconus, which causes the cornea to take on a cone shape.

"This is a major discovery that will mean that ophthalmology textbooks will literally need to be re-written," says Dua. "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."

Popular Science notes that knowledge of the new layer "could dramatically improve outcomes for patients undergoing corneal grafts and transplants." Because when you're gently knifing into the eyeball with a scalpel, it's probably a good idea to know exactly what you're cutting into.