Fuchs' Endothelial Dystrophy
Signs and Symptoms
Late hereditary (Fuchs’) endothelial dystrophy is usually seen in the fifth or sixth decade of life. It is more common in women than men, usually present in both eyes, and usually of dominant inheritance. The dystrophy itself stems from a malfunction of the corneal endothelium, which is the back layer of the cornea (the clear front 'window' of the eye). This may ultimately cause the disruption of the cornea and some haziness or cloudiness to vision.
Symptoms may include reduction in the clarity of vision, irritated feeling to eyes, and pain upon waking. Corneal dystrophies tend to run in families and have no association with systemic diseases or environmental factors. It is associated with a slightly increased occurrence of glaucoma.
The cornea consists of five layers. The endothelial cell layer is a single layer of hexagonal cells. It shows great metabolic activity and is actively involved in the maintenance of corneal dehydration. Following trauma or injury, the surrounding endothelial cells slide over to the injured area. There is no reproduction of the cells in the adult endothelium. This focal enlargement and/or change in shape of the endothelial layers can be seen using special microscopic techniques and is called polymegathism and pleomorphism, respectively.
The progression of Fuchs’ Dystrophy is complex, but can best be divided into three stages, which usually span 10 to 20 years. In the first stage the patient initially has no symptoms, but shows irregularly distributed 'guttata' and geographically arranged pigment dusting.
In the second stage the patient develops stromal and epithelial swelling, with symptoms of glare and hazy vision. Visual acuity is usually 20/30 or better. As the swelling increases, the benefit of better vision late in the day is lost, and pain and light sensitivity may develop.
Some patients progress to the third phase. In this phase, the stromal edema disappears as the middle layer of the cornea scars, and the patient becomes more comfortable even though vision can be severely reduced.
The treatment for Fuchs’ endothelial dystrophy varies, depending upon the severity of the disease, and may range from simple observation, to hypertonic drops, to surgical intervention. Patients with early corneal swelling and blurring may be treated conservatively at first with 5% sodium chloride drops four times a day and 5% sodium chloride ointment at bedtime. (Use of a hair dryer held at arms length from the surface of the cornea, in combination with the hyperosmotic agents, may dry out the corneal surfaces and decrease the time the blur persists.)
A thin soft contact lens (bandage lens) is sometimes beneficial in alleviating patient discomfort. Any elevation of internal eye pressure forces more fluid into the cornea across the compromised endothelium. Appropriate pressure reduction with topical and or oral ocular antihypertensive medications may decrease the progression and symptoms secondary to corneal edema. Corneal transplants for Fuchs’ dystrophy account for approximately 10 percent of all corneal grafts performed. Fortunately, most people with Fuchs' Dystrophy don't progress to the point where a corneal transplant is necessary.