Welcome to question of the day # 67

Welcome to question of the day # 67

A 92-year-old man with a white cornea following complicated cataract surgery on his right eye presents for an eye examination. What is going on?

There are only two ingredients in this recipe; eye surgery and an opaque cornea in the operated eye. This sounds very much like corneal decompensation.

This often occurs as a response to injury from incidental corneal contact by instruments during intraocular surgery (such as cataract extraction); chemical injury from the improper use of intraocular drugs, drugs containing preservatives, or from residues from inadequate rinsing of detergents or other residues from surgical instruments.

The cornea contains collagen and cells in an ordered arrangement the spacing of whichmakes the cornea optically transparent. The corneal endothelium control hydrationsandis permeable to nutrients and other molecules from the aqueous humor because blood vessels do not supply these. The endothelium maintains corneal clarity by being a barrier to fluid movement into the cornea and a pump that moves ions, and draws water osmotically, from the stroma into the aqueous humor.

When corneal endothelial cells aredamaged, this delicate balance is disrupted, and more fluid enters the cornea than is pumped out. The excess fluid in the cornea disrupts the critical spacing of the collagen; the cornea loses its transparency and looks white to observers. The patient’s visual acuity is poor in the affected eye.

Corneal endothelial decompensation sometimes requires corneal transplantation. The patient deserves an opinion from an ophthalmologist specialising in corneal disease.