What are the risks involved in having a cornea transplant for a person who has had extensive glaucoma surgery in past years?

Glaucoma and previous glaucoma surgery increases risk for corneal transplantation for a number of reasons. History of glaucoma surgery can increase the rate of transplant failure of up to 50 percent and one of the top causes of transplant failure is uncontrolled intraocular eye pressure.

First, any hardware in the front of the eye, such as glaucoma valves (tiny implants that help treat glaucoma), can damage the corneal endothelium (innermost layer of the cornea, the front clear window of the eye) with each blink of the eye if they are positioned close to the cornea. Even if the valves are not closely placed to the back of the cornea, the flow of the fluid inside the eye is altered and that can also produce damage and cause the transplant to fail. Having hardware in the eye also may make partial thickness corneal transplantation (DSAEK or DMEK) challenging to perform and cause the graft (the normal tissue that replaces the diseased cornea) to not attach to the rest of the cornea.

In addition, corneal transplantation makes glaucoma much more difficult to control. Corneal transplant patients are often on a high dose of topical steroids which can increase eye pressure. After transplant surgery, there is a substantial amount of inflammation and scarring of the fluid drainage canals tissue inside of the eye which can alter the eye's natural ability to regulate eye pressure.

Even though glaucoma and glaucoma surgery increases risk for corneal transplantation, often patients need treatment for both of these conditions as the only way to rehabilitate vision.