Fuchs endothelial dystrophy is a progressive eye condition affecting the cornea, the clear, dome-shaped front part of the eye. This disorder primarily impacts the innermost layer of corneal cells, leading to fluid accumulation and impaired vision.
Understanding Fuchs Endothelial Dystrophy
The cornea has multiple layers, and its transparency relies on the proper function of the endothelium, a single layer of cells on its inner surface. These endothelial cells act as a pump, actively removing excess fluid from the corneal tissue to maintain its clarity and shape. In Fuchs endothelial dystrophy, these cells gradually deteriorate and die off.
As endothelial cells are lost, their ability to pump fluid diminishes, leading to fluid buildup within the cornea. This fluid accumulation, or corneal edema, causes the cornea to swell and become cloudy. A distinguishing feature of Fuchs dystrophy is the formation of abnormal deposits called guttata on Descemet’s membrane, the layer beneath the endothelium. These changes interfere with the cornea’s ability to focus light, resulting in blurred vision.
Recognizing the Symptoms
Symptoms of Fuchs endothelial dystrophy often develop slowly over many years, becoming noticeable in individuals over 50. A common initial symptom is blurred or hazy vision upon waking, which gradually improves throughout the day. This morning blur occurs because closed eyelids during sleep prevent fluid evaporation from the corneal surface, worsening swelling.
As the disease progresses, the corneal swelling becomes more persistent, causing vision to remain blurry all day. Individuals may also experience increased sensitivity to bright light and see glare or halos around lights. Other discomforts include a gritty sensation in the eyes or, in advanced stages, pain from ruptured blisters on the corneal surface.
Causes and Risk Factors
Fuchs endothelial dystrophy has a strong genetic component, often running in families with an autosomal dominant inheritance pattern. This means that if one parent has the condition, their child has a 50% chance of inheriting it. While genetic predisposition plays a significant role, some cases can occur spontaneously without a clear family history.
Research has identified several genes associated with an increased risk. The TCF4 gene has been linked to the severity of the condition, with a specific genetic marker influencing disease risk. Beyond genetics, age is a primary risk factor, as symptoms manifest after age 50. The condition is also observed more frequently in women than in men.
Diagnosis and Treatment Options
Diagnosing Fuchs endothelial dystrophy involves a comprehensive eye examination by an ophthalmologist. A slit-lamp examination is used to observe the characteristic guttata, which appear as small bumps on the back surface of the cornea, and to assess for corneal edema. Pachymetry, a test that measures corneal thickness, helps quantify the extent of swelling. Specular microscopy provides a detailed view of the endothelial cells, allowing assessment of their density and health.
Treatment approaches for Fuchs dystrophy vary based on the disease stage and severity. In early stages, conservative management focuses on reducing corneal swelling and alleviating symptoms. Hypertonic saline drops or ointments are often prescribed to draw excess fluid out of the cornea, to reduce morning blurriness.
When vision becomes significantly impaired due to persistent swelling, surgical intervention may be considered. Endothelial keratoplasty, a partial corneal transplant, is the preferred surgical approach for advanced cases. This procedure selectively replaces only the diseased innermost layers of the cornea while leaving the healthy outer layers intact.
Two main types of endothelial keratoplasty are commonly performed: Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) and Descemet’s Membrane Endothelial Keratoplasty (DMEK). DSAEK involves transplanting the endothelium, Descemet’s membrane, and a thin layer of corneal stroma. DMEK uses an even thinner graft of only the endothelium and Descemet’s membrane. Both procedures aim to restore clear vision by replacing the dysfunctional endothelial cells with healthy donor tissue, thereby allowing the cornea to maintain its proper fluid balance.