Fuchs Endothelial Dystrophy
Fuchs Endothelial Dystrophy is a slowly progressive, bilateral corneal condition (occurs in both eyes) that is caused by corneal endothelial cells loss.
What is the important of Corneal Endothelial Cells?
These cells act as a barrier between the corneal stromal tissue and the aqueous humor. They have special pump mechanism to pump extra fluid out from the corneal tissue and also to pump fluid from aqueous humor in case of dehydration of corneal tissue. When these cells are lost, this pump mechanism is lost, and fluid starts to accumulate in corneal tissue causing corneal edema.
Corneal endothelial cells have no abilities to regenerate which means that cells that are lost can’t be replaced by new endothelial cells but the remaining endothelial cells will expand to cover the places of dead cells and with time the pump function of the remaining endothelial cells is not enough to keep the fluid outside the corneal tissue.
What is the inheritance of Fuchs Endothelial Dystrophy?
Most of the cases are sporadic, which mean have no inheritance connection but some can be inherited as autosomal dominant. It occurs in old age and women are affected more than men.
Diagnosis of Fuchs Endothelial Dystrophy
Eye doctor can diagnose Fuchs Endothelial Dystrophy by:
1- Clinical Examination
This disease pass through three stages and each stage has its each clinical signs and symptoms.
2- Specular Endothelial Microscopy
It is used to photograph the corneal endothelial cells. The shape, the size and density of cells can be recognized by this test. Endothelial cells in Fuchs endothelial dystrophy have abnormal shape, size and also density. The normal density is 3000 cells per mm square.
3- Corneal Pachymetry
Measures central corneal thickness which increases in this disease.
What are the clinical stages of Fuchs Endothelial Dystrophy?
Stage 1, Corneal Guttata
These abnormal endothelial cells will secret also abnormal Descemet membrane. This membrane will have abnormal warts and extensions and on clinical examination the cornea will have beaten metal appearance and also some melanin or pigments can be deposit on the endothelial surface. The guttata starts on the center of the cornea and with time it spreads to the periphery.
This stage is asymptomatic and it is diagnosed accidentally during regular eye examination.
Stage 2, Endothelial Decompensation
At this stage, the pump function starts to fail and fluid starts to accumulate on corneal tissue with the formation of corneal edema. The edema starts also on the center and spreads to the periphery. The edema starts also from back to front corneal layers. It starts in the stromal layer and then spread to the superficial epithelial layer.
Patients start to complain of blurred vision especially in morning because during night, the cornea is covered by the eyelid and fluid accumulate in the cornea but during the day and because of the evaporation, the amount of edema is decreased and vision improved. Patients also complain of glare, photophobia and halos around lights.
Stage 3,Persistent Corneal Edema
Persistent epithelial edema can result in the formation of corneal bullae and cysts which are filled with fluid. These cysts are formed in the front surface of the cornea and when they rupture they will cause pain, photophobia and excessive tearing. Recurrent formation and rupture of cysts can cause corneal scaring which can cause severe blurred vision.
Treatments of Fuchs Endothelial Dystrophy
So far there is no cure for Fuchs endothelial dystrophy. Treatments will focus on reduce the symptoms and complications of the dystrophy and at the end stage with severe loss of vision, corneal graft can be the only option.
Symptomatic treatments of Fuchs Endothelial Dystrophy are
1- Saline Eye Drops
This eye drops also called Sodium chloride. It should be hyper-osmotic to pull out the fluid from corneal tissues. It can be either eye drops or ointment.
2- Warm Dry Air
A hair Dryer can be used to evaporate the eye especially on awakening. You should keep the dryer away from your eye. Evaporation can temporary improve.
3- Lower Intraocular Pressure
With normal intraocular pressure and abnormal endothelial cells, the fluid will be pushed inside the cornea. Lowering intraocular pressure and help to reduce the amount of fluid that is pushed inside the cornea.
4- Bandage Contact Lens
This type of contact lens can be used in patients with bullae. It helps to reduce pain.
5- Pain Relief
Pain can be reduced by bandage contact lens, NSAIDs Eye drops and cycloplegic eye drops such as Cyclopentolate and atropine eye drops.
6- Antibiotics Eye Drops
Formation of corneal bullae can increase the risk of corneal infection. Antibiotics eye drops can be used in this case.
7- Peripheral Anterior Stromal Puncture
can be used to form corneal scar tissue, thus reduce the formation of bullae but this is not a definite treatment especially for center bullae.
8- Cornea Transplant
It is indicated in patients with severe blurred vision, severe corneal scar and bullous keratopathy. It is either penetrating keratoplasty in which the whole cornea is replaced or DESK surgery (Descemet's stripping with endothelial Keratoplasty) which is a new surgical technique in which only the endothelial layer is removed and replaced.