There is a disease of the cornea whose most characteristic sign is, of all things, the time of day: vision is blurred in the morning and clears as the day goes on. This is Fuchs’ dystrophy — an inherited, slow disease of the innermost layer of the cornea, the endothelium. This page explains what happens in the cornea, the symptoms, how it is diagnosed, and the treatment path — from monitoring and drops to transplanting the endothelial layer.
What Fuchs’ dystrophy is
The cornea is the clear window at the front of the eye, and its clarity depends on staying relatively “dry.” Responsible for this is a thin layer of cells on its inner side — the endothelium — which acts as a pump, drawing out fluid that seeps in. In Fuchs’ dystrophy the endothelial cells weaken and dwindle gradually over years (inherited in most cases), and the pump becomes less efficient. Once it can no longer keep pace, the cornea absorbs fluid, swells and clouds — and vision suffers. Tiny bumps called guttata also appear on the endothelium, a characteristic sign of the disease.
The symptoms — and why mornings are worse
The disease progresses slowly, usually appears from middle age onward, and is more common in women. The most characteristic sign: blurring that is worse in the morning and improves through the day. The reason is simple — at night, with the eyes closed, there is no evaporation from the front of the cornea and fluid accumulates in it; as the eyes open and evaporation takes place through the day, the cornea dries a little and vision clears. Other symptoms: glare and halos around lights, a sense of haze, and in advanced stages pain or discomfort if tiny blisters form on the corneal surface.
How it is diagnosed
The diagnosis is made in a doctor’s examination with a slit lamp, in which the guttata and swelling are seen. For a more precise assessment, corneal thickness measurement (pachymetry) and imaging of the endothelial layer (specular/endothelial microscopy), which counts cell density, are used. This assessment is especially important when planning cataract surgery, because it predicts how well the cornea will “hold up” to surgery.
The link to cataract surgery
Fuchs’ dystrophy and cataract often appear together at the same age, and that raises an important decision. Cataract surgery stresses the endothelium somewhat, and in an eye with borderline Fuchs’ it can accelerate the swelling. So before cataract surgery in an eye with Fuchs’, the state of the endothelium is assessed and a decision is made: whether to perform cataract surgery alone, carefully, or to combine cataract surgery with an endothelial transplant from the outset (a combined procedure). The cataract operation itself is covered in cataract surgery.
Treatment — by stage of the disease
Treatment follows the severity of the disease and the degree of visual impairment:
- Monitoring and drops. In early stages, while vision is still good, monitoring is usually enough. Drops or ointment of a concentrated (hypertonic) saline solution can “draw” fluid out of the cornea and reduce the blur, especially in the morning.
- Endothelial transplant (DMEK / DSAEK). When the swelling significantly impairs vision, the solution is to replace only the damaged endothelial layer — not the whole cornea — using donor tissue. The precise, standard method today is DMEK, in which an especially thin layer is transplanted, allowing fast recovery and high visual quality; DSAEK, a slightly thicker layer, is reserved for complex cases. This is a form of partial corneal transplant — covered in corneal transplant.
- An emerging option for select cases (DSO). In some patients with early disease and a healthy peripheral endothelium, only the damaged center can be removed (Descemet Stripping Only), letting the healthy cells “crawl” over and cover the area, sometimes aided by drops from the rho-kinase inhibitor group. This is a relatively new approach, suited to select cases only, not everyone.
When to get examined
Blurring that is worse in the morning, increasing glare, or vision that grows hazier over the years — especially with a family history of the disease — are good reasons to be examined. Early diagnosis allows monitoring, correct timing of cataract surgery if needed, and choosing the right treatment at the right time. Prof. Michael Mimouni is a cornea specialist, and the examination assesses the state of the endothelium and what suits your eye. Get in touch to arrange an examination. On other eye diseases, see eye diseases.
The information on this page is general and not a substitute for a personal examination and medical advice. Diagnosis and treatment are determined only after a full eye examination.
Frequently asked questions
What causes Fuchs' dystrophy?
In most cases it is an inherited disease: the cornea's endothelial cells, which do not regenerate, weaken and dwindle faster than normal over the years. It is more common in women and usually appears from middle age onward.
Why is vision worse in the morning?
At night, with the eyes closed, there is no evaporation from the cornea and fluid accumulates in it, so it is more swollen in the morning. Through the day, as the eyes open and evaporation occurs, the cornea dries a little and vision clears. This is a very characteristic sign of the disease.
Does the whole cornea need to be transplanted?
No. In Fuchs' only the damaged inner layer (the endothelium) is replaced, in a partial transplant — DMEK or DSAEK — not the full thickness of the cornea. Recovery is faster and more precise than a full transplant.
I have both Fuchs' and a cataract — what is done?
The state of the endothelium is assessed before surgery. Sometimes cataract surgery alone is done carefully, and sometimes cataract surgery is combined with an endothelial transplant from the outset. The decision depends on the endothelial cell density and the degree of swelling.
