As you can see from the accompanying figure, the most appropriate corneal transplant depends heavily on the layers affected.
There are many possible indications for corneal transplantation, including corneal anomalies, corneal degenerations and corneal dystrophies.
Corneal anomalies can include trauma or infection that can lead to scarring and irregular astigmatism as well as idiopathic problems such as pseudophakic bullous keratopathy (chronic post-cataract extraction corneal edema) and decompensation of donor tissue, leading to the need for repeat transplant.
Corneal degenerations are metabolic and age-related and, therefore, occur later in life. They can be bilateral, but are often asymmetric. They first affect the peripheral cornea, then move centrally and have associated inflammation and vascularization. Examples include Salzmann’s nodular degeneration and band keratopathy. Corneal degenerations may call for surgical intervention but rarely corneal transplantation.
Corneal dystrophies are hereditary, with early onset, usually in the first or second decade of life. They are bilateral and symmetric and start centrally; therefore, they are often more visually significant than degenerations. Corneal dystrophies include congenital corneal ectasias like KCN and pellucid degeneration.
Join us next month as we review preoperative considerations for corneal transplantation.