In a healthy cornea, a layer of cells called endothelial cells and located on the back side of the cornea maintains the clarity of the cornea by pumping water from the cornea into the inside of the eye.
A congenital disease such as Fuchs dystrophy or trauma induced by cataract surgery, glaucoma surgery, or any intraocular surgery can cause a decrease in the number of endothelial cells. When the cell count gets too low, water is no longer pumped out of the cornea and this induces corneal edema.
In an advanced stage, corneal edema can cause a significant decrease in vision in addition to severe pain due to the rupture of the epithelial bubbles (filled with fluid).
Symptomatic treatment includes hyperosmotic eye drops to decrease corneal edema (5% sodium chloride) and contact lenses to reduce discomfort.
The curative treatment is surgical and aims to replace the damaged tissue. The most advanced type of surgical treatment is Descemet Membrane Endothelial keratoplasty (DMEK) .