In Fuchs endothelial dystrophy, which function is impaired in the innermost corneal layer leading to edema?

In Fuchs endothelial dystrophy, which function is impaired in the innermost corneal layer leading to edema?

• A. Pumps fluid out of the cornea
• B. Produces tears
• C. Regulates pupil size
• D. Secretes aqueous humor

Answer: (A)

Corneal endothelium is the innermost layer and its job is to keep the cornea dry by actively pumping fluid out of the stroma into the anterior chamber. In Fuchs endothelial dystrophy, endothelial cells are lost or dysfunctional, so this pumping function declines. Fluid then accumulates in the stroma (and sometimes the epithelium), leading to corneal edema and a cloudy, swollen cornea. That’s why the correct idea is that the pump function—moving fluid out of the cornea—is impaired. The other options describe functions outside the endothelium’s role: tear production by the lacrimal system, pupil size regulation by the iris, and aqueous humor secretion by the ciliary body. None of those cause the edema seen in Fuchs.

Corneal endothelium is the innermost layer and its job is to keep the cornea dry by actively pumping fluid out of the stroma into the anterior chamber. In Fuchs endothelial dystrophy, endothelial cells are lost or dysfunctional, so this pumping function declines. Fluid then accumulates in the stroma (and sometimes the epithelium), leading to corneal edema and a cloudy, swollen cornea.

That’s why the correct idea is that the pump function—moving fluid out of the cornea—is impaired. The other options describe functions outside the endothelium’s role: tear production by the lacrimal system, pupil size regulation by the iris, and aqueous humor secretion by the ciliary body. None of those cause the edema seen in Fuchs.