The clear tissue at the front of the eye is the cornea; in order to have clear vision, the tissue of the cornea needs to remain thin and transparent. The inner layer of the cornea called the endothelium keeps the cornea clear, and if there is a problem with the cells in this layer, corneal edema may result. A potential side effect after cataract surgery is corneal edema. Pre-existing conditions, damage to the endothelial layer or increased intraocular pressure can cause the cornea to become cloudy. The treatments for corneal edema depend on the cause, the length of time and the severity of the edema.
Mild corneal edema that develops after cataract surgery may not require any treatment. According to the University of Washington Medical Center website, the surgeon may observe the edema. Often the swelling will resolve in about one week, as noted on the Review of Optometry website.
Saline Drops or Ointments
For some patients with mild corneal edema, the surgeon may prescribe concentrated saline drops or ointment to reduce the thickness of the cornea, according to the University of Washington Medical Center website. The saline medication will pull some of the fluid out of the cornea because the solution is very concentrated.
Sometimes the pressure inside of the eye becomes elevated because of inflammation in the eye or residual materials used during the surgery; this causes the drainage angle inside of the eye to be blocked. These circumstances lead to elevated intraocular pressure. According to the Review of Optometry website, if the eye pressure is between 25mm and 35mm of mercury after cataract surgery, the surgeon should begin eyedrops that lower eye pressure. If the eye pressure is higher, the surgeon may undertake different procedures to lower the pressure more immediately. Once the intraocular pressure is lowered, the cornea should become clear again in most cases.
In some cases, the corneal swelling does not resolve by itself or with the saline medications. The edema may continue to progress over time with more edema in the cornea and blisters on the outer layer of the cornea. Some patients who have a condition called Fuch's dystrophy prior to cataract surgery may be at higher risk for corneal edema. If the edema causes significant vision impairment, the surgeon may perform a corneal transplant to improve the vision, according to the University of Washington Medical Center website. In this procedure, the surgeon removes a portion of the diseased cornea and replaces it with a donor cornea.
Deep Lamellar Endothelial Keratoplasty/Descemets Stripping Endothelial Keratoplasty
Some surgeons replace only the inner or endothelial layer of cells of the cornea in cases of advanced corneal edema after cataract surgery. Since the endothelial cells are responsible for removing the fluid from the cornea, replacing the endothelial cells only may resolve the problem with fewer side effects than a full corneal transplant, according to the Endothelial Keratoplasty website. The procedures that replace the endothelial cells are called deep lamellar endothelial keratoplasty or Descemets stripping endothelial keratoplasty.