Bullous Keratopathy
(See also Introduction to Corneal Disorders.)
Bullous keratopathy is caused by edema of the cornea, resulting from failure of the corneal endothelium to maintain the normally dehydrated state of the cornea. Most frequently, it is due to Fuchs corneal endothelial dystrophy or corneal endothelial trauma. Fuchs dystrophy is a genetic disorder that causes bilateral, progressive corneal endothelial cell loss, sometimes leading to symptomatic bullous keratopathy by age 50 to 60. Fuchs dystrophy may be autosomal dominant with incomplete penetrance. Another frequent cause of bullous keratopathy is corneal endothelial trauma, which can occur during intraocular surgery (eg, cataract removal) or after placement of a poorly designed or malpositioned intraocular lens implant. Bullous keratopathy after cataract removal is called pseudophakic (if an intraocular lens implant is present) or aphakic (if no intraocular lens implant is present) bullous keratopathy.
Subepithelial fluid-filled bullae form on the corneal surface as the corneal stroma (the deeper dense connective tissue layer of the cornea) swells, leading to decreased visual acuity, loss of contrast, glare, and photophobia. Sometimes bullae rupture, causing pain and foreign body sensation. Bacteria can invade a ruptured bulla, leading to a corneal ulcer.
The bullae and swelling of the corneal stroma can be seen on slit-lamp examination.
Treatment requires an ophthalmologist and includes topical dehydrating agents (eg, hypertonic [5%] sodium chloride 5% drops and ointment), intraocular pressure–lowering agents, occasional short-term use of therapeutic soft contact lenses for some mild to moderate cases, and treatment of any secondary microbial infection. Corneal transplantation is usually curative.
