Corneal edema is an irreversible complication of cataract eye surgery. Corneal edema is a combination of two conditions, aphakic bullous keratopathy (ABK) and pseudophakic bullous keratopathy (PBK). It results in the development of stromal and inter cellular epithelial edema as corneal edema manifests and worsens. Development of bullae leads to epithelial edema. That is why it is referred as bullous keratopathy.
The rate of incidence has decreased dramatically as surgical lens and techniques have improved. But still it is an important cause of visual impairment.
Pathophysiology Of Corneal Edema
The ability of the cornea to remain dehydrated affects the corneal transparency. The endothelium and epithelium are both semipermeable membranes that controls the flow of electrolytes and water into the cornea. Hypertonic solution forms due to the evaporation of the water from the corneal tear film. It draws out the fluid from the cornea. Intraocular pressure drives fluid into the cornea.
Frequency In United States
Roughly, it has been estimated that 0.1% of patients undergoing cataract surgery will develop PBK. About 33% of corneal transplants for treating ABK and PBK were performed during the years 1984-1989 ( United States). The number of cases has decreased since then. But there has been an increase in the number of cataract surgeries performed.
Occurrence In Race
There are no known link of PBK with race which exists. But it has been observed that patients of North European Descent are more prone to have Fuchs corneal disorder. This disorder leads to the formation of corneal edema.
Is PBK Gender And Age Specific?
Fuchs corneal dystrophy occurs approximately 3 times more frequently in women than in men. Older patients are more likely to have this problem if they have less endothelial reserve.
