Fuchs Dystrophy and Cataracts
What is a cataract?
A cataract is the clouding of the lens in the eye. Normally, the lens helps focus the light onto the retina (the film on the back of the eye). When the lens becomes clouded, the picture that the person sees becomes clouded, as well.
Cataracts develop naturally among aging individuals. More than half of all people above sixty years old suffer from cataracts. Removal of cataracts is the most common eye surgery. 1.4 million cataract surgeries are performed in the United States each year.
From the files of John D. Gottsch, MD
Fuchs Endothelial Corneal Dystrophy (FECD) and Cataracts
Some people with cataracts also have Fuchs Endothelial Corneal Dystrophy (FECD). If a Fuchs patient undergoes cataract surgery, the fragile endothelial cells of the cornea may be damaged. (The endothelial cells are those cells at the very back of the cornea. The endothelial cells deteriorate in patients with FECD.) The loss of too many of these cells can lead to edema (swelling) of the cornea. This edema can then sometimes lead to painful corneal bullae (blisters), deterioration of vision, and eventually, the need for a corneal transplant.
In summary, in a patient with FECD, a cataract surgery may hasten the need for a corneal transplant. Because of this risk, the corneas of FECD patients are examined carefully before cataract surgery. Sometimes, the eye doctor will decide that the patient should have both cataract surgery and a corneal transplant at the same time. By doing this, two separate surgeries are combined into one procedure, and recovery time is greatly reduced.
Recent research has helped doctors figure out when a Fuchs patient can have simple cataract surgery and when a Fuchs patient should have a combined surgery (cataract surgery plus corneal transplant). These researchers showed that many Fuchs patients with corneas thinner than 640 microns can usually have simple cataract surgery. (A micron is a very tiny unit of measurement. Each micron is 0.00004 inches long.)
Whenever a person with FECD has cataract surgery, the surgeon uses special jelly-like material called viscoelastic gel. Viscoelastic gel is put inside the eye to protect the back of the cornea during the surgery. The viscoelastic gel is then taken out again at the end of the surgery. This gel has been shown to greatly decrease endothelial cell loss during cataract surgery.
Ophthalmologic researchers are trying to figure out if there is a minimum number of endothelial cells that everyone has to have in order to see properly. Preliminary research, however, indicates that no absolute number exists for this threshold value. Instead, it seems to vary from patient to patient.
Fuchs and Laser Vision Correction
Any trauma to the cornea can be detrimental to the endothelium, and thereby cause Fuchs symptoms to worsen faster. Fuchs patients are advised against undergoing cosmetic corneal surgery such as Laser Vision Correction.
To read a scientific paper on this subject, please click here.