Bullous Keratopathy

Bullous keratopathy

Bullous keratopathy is a condition characterized by swelling of the cornea due to endothelial damage.^[1]

Epidemiology

Bullous keratopathy is most common among older people. The incidence has decreased since the advent of intraoperative viscoelastic agents that protect the corneal endothelium and the decline of iris plane and anterior chamber intraocular lenses usage. A study at the University of Toronto shows that pseudophakic bullous keratopathy is the 3rd leading indication of penetrating keratoplasty.^[1]

Causes

Bullous keratopathy often occurs after an eye surgery such as removal of cataract.^[1] Bullous keratopathy is due to corneal edema brought about by failure of the corneal endothelium to keep up the dehydrated condition of the cornea. Most commonly, the condition is caused by Fuchs' corneal endothelial dystrophy which occasionally leads to symptomatic bullous keratopathy when a person reaches 50 to 60 years old. Fuchs' corneal endothelial dystrophy can take place during an intraocular surgery like cataract removal or when an ill-designed intraocular lens has been placed or when an implant has been placed in the wrong position.

When bullous keratopathy is obtained after removal of cataract, it is properly termed pseudophakic bullous keratopathy (present intraocular lens implant) or aphakic bullous keratopathy (absent intraocular lens implant).^[2]

Signs and Symptoms

Signs include epithelial and stromal edema, microcysts and bulla formation and subepithelial scarring from resolved chronic edema. Symptoms include mild to severe decreased visual acuity, pain from epithelial and subepithelial breakdown of the bulla, tearing, light sensitivity and decreased or loss of corneal sensation in advanced stage.^[3]  At times,  the rupture of bullae causes sensation of foreign body. A corneal ulcer may develop when bacteria sets in.^[2]

Diagnosis

Eliciting past eye surgery in the history is useful in diagnosis. On physical examination, there is a characteristic presentation of a swollen and cloudy cornea. Blisters on the surface are also observed.^[1] Slit-lamp is an often used tool.^[2]

Treatment

Treatment of bullous keratopathy is aimed at decreasing the amount of fluid in the cornea. Hypertonic eye drops are often used. Soft contact lenses can be utilized to lessen discomfort. In severe cases, corneal transplantation is indicated.^[1]

References:

1. http://www.images.missionforvisionusa.org/anatomy/2005/11/bullous-keratopathy-of-cornea.html
2. http://www.merckmanuals.com/professional/eye_disorders/corneal_disorders/bullous_keratopathy.html
3. http://dro.hs.columbia.edu/bullousk.htm

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