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Fuchs’ Dystrophy

Fuchs’ Dystrophy (FD) is named after a famous Austrian ophthalmologist and is pronounced “Fooks” rather than any other way! Technically, it can also be called “Fuchs’ Corneal Endothelial Dystrophy”, so let’s look at these descriptors. FD is indeed a disease of the cornea, the transparent membrane over the coloured iris of the eye. The cornea must be clear and appropriately curved for good vision: FD can reduce clarity. The word endothelial refers to the site of the abnormality: the inner layer of the cornea, called the endothelium. This is a single layer of cells whose function is to pump water out of the cornea and into the eye. The importance of this is that it prevents the cornea becoming “water-logged” and opaque. Unfortunately, the endothelial cells cannot replicate or repair themselves, and become fewer and fewer with age. In FD, the endothelial cells are abnormal and pump water less well.

Many patients with FD don’t have much in the way of symptoms. However in a minority the endothelial cells work so poorly that the cornea starts to become waterlogged. These patients typically report misty vision on waking which initially resolves after a short period each day. However, with the passage of time, the duration gets longer and longer until it is permanent.

Medical (non-surgical) treatment isn’t very effective. Hypertonic saline drops are available to try to suck water out of the cornea, but many of us wonder if the osmotic effect can cause damage to the already damaged corneal cells. Less elegant but more effective is the use of a hair-drier held at arm’s length and used to dehydrate the cornea by a wind-evaporation effect.

In general, surgery is required in the form a of a corneal transplant or corneal graft. Whilst a penetrating keratoplasty (PK) used to be the standard of care, the modern management is an “endothelial keratoplasty” or EK. The advantage of this surgery is that only the diseased layer of the cornea is replaced, with less rejection and more rapid restoration of vision without the need for difficult glasses.

This can be either a Descemet’s Stripping Endothelial Keratoplasty (DSEK) or a modification called DSAEK (where the A indicates a step has been automated) or a Descemet’s Membrane Endothelial Keratoplasty (DMEK) which is now the preferred procedure. DMEK is a challenging procedure, as the donor graft is a membrane that rolls up into a scroll and has to be unfolded the right way up inside the recipient’s eye, and then made to stick on in the right place! Invented in Holland, it is obviously a better procedure than a PK for endothelial disease in general and FD in particular.