Fuchs' Endothelial Corneal Dystrophy

Our vision relies on the cornea — the clear front window of the eye — remaining transparent. A crucial part of that clarity is maintained by a delicate, single layer of cells on the cornea’s inner surface called the endothelium. These cells act like tiny, tireless pumps, removing excess fluid from the cornea to keep it thin and clear. In Fuchs’ Endothelial Corneal Dystrophy, these endothelial cells gradually deteriorate and decrease in number.

As these pump cells become less effective, fluid accumulates within the cornea and causes it to swell — a condition known as corneal oedema. The swelling leads to cloudiness and a loss of transparency, ultimately blurring vision.

What happens in Fuchs’ dystrophy

Fuchs’ dystrophy is a slowly progressive, often inherited condition. It typically affects both eyes, though not always symmetrically. In the early stages, patients may not notice any symptoms. As the disease advances, the endothelial cell count drops and the pumping function diminishes.

• Guttae formation. One of the earliest signs, visible to an ophthalmologist during an eye examination, are tiny bumps called guttae on Descemet’s membrane — the layer just beneath the endothelium. These are abnormal deposits produced by stressed endothelial cells.
• Corneal oedema. As more cells are lost, the remainder cannot keep up with fluid removal. The cornea begins to swell, initially causing blurred vision that is worse in the morning — the eyelids are closed during sleep, preventing evaporation — and improves as the day goes on.
• Advanced stages. Later, the swelling can become constant. Painful blisters (bullae) may form on the corneal surface if the oedema is severe, a condition known as bullous keratopathy. Vision can become significantly impaired, affecting reading, driving and daily activities.

Who is typically affected

• Fuchs’ dystrophy is more common in women than in men.
• It usually begins to manifest in middle age, in the forties and fifties, though symptoms may not become problematic until later.
• A family history increases the risk, as the condition often has a genetic component.

Common symptoms

• Blurred or hazy vision, often worse on waking
• Glare and light sensitivity
• Difficulty seeing in dim light
• Haloes around lights
• Fluctuating vision through the day
• In advanced cases, eye pain or a gritty sensation if blisters form

Diagnosis

An ophthalmologist can diagnose Fuchs’ dystrophy during a comprehensive eye examination using a slit lamp. Specific tests include:

• Specular microscopy — to visualise and count the endothelial cells and assess their shape and size.
• Pachymetry — to measure corneal thickness, which indicates the degree of swelling.

Treatment options

Treatment depends on the severity of symptoms and the stage of the disease.

Early stages

If vision is not significantly affected, no treatment may be necessary — only regular monitoring.

Mild symptoms

Hypertonic saline drops or ointments (for example 5% sodium chloride) can help draw fluid out of the cornea, temporarily improving clarity, especially in the morning. A hairdryer held at arm’s length and directed towards the eyes for a few minutes after waking can also help dehydrate the cornea.

Advanced stages with significant vision loss

When vision is meaningfully impaired by corneal oedema, surgery is usually recommended.

• DMEK — Descemet’s Membrane Endothelial Keratoplasty is now often the preferred surgical approach for Fuchs’ dystrophy. It involves selectively removing the diseased Descemet’s membrane and endothelium and replacing them with a thin layer of healthy donor tissue. DMEK offers the potential for rapid visual recovery and excellent visual outcomes.
• DSAEK/DSEK — Descemet’s Stripping Automated Endothelial Keratoplasty is another form of endothelial keratoplasty, using a slightly thicker donor graft than DMEK.
• Penetrating keratoplasty — a full-thickness corneal transplant may be considered if there is significant corneal scarring in addition to endothelial dysfunction, or if other techniques are not suitable.

Fuchs’ dystrophy can be a challenging condition, but with modern diagnostic tools and advanced surgical techniques such as DMEK, the outlook for restoring clear vision is very positive. Early detection and appropriate management are key.