By Dr.Mahipal S Sachdev Chairman, Centre for Sight
Fuchs’ Dystrophy a corneal eye disease happens when the innermost layer of the corneal cells undergoes degenerative changes. Endothelium, the cell layer in the cornea responsible for maintaining appropriate amounts of fluid in the cornea and keep it clean and clear, dies off with the progression of the disease. This happens due to the failure of the layer to pump out the excess fluid accumulation causing corneal swelling thereby affecting the vision. Gradually the condition is known to affect both the eyes causing cloudy, hazy and declining vision.
What causes Fuch’s Dystrophy?
People suffering from this disorder usually get up with a blurry vision in the morning that gradually worsens throughout the day. The genetic basis seems quite complex with severities and degrees varying through the family members. Though genetic reasons attribute to about 50% of the cases, idiopathic cases where usually symptoms persist around 40-50 years of age are coming up even in people under the age of 30 years. According to several studies it has also been found that females are twice likely to develop the condition than male. Risk factors like smoking and diabetes are also known to trigger the condition.
What are the symptoms?
In the initial stages blurry or foggy vision is accompanied by sensitivity to light and glare that decreases the vision in dim or bright light. Progression of the condition is characterized by severe eye pain, difficulty to see in the night, poor vision and a sensation of presence of some particle in the eye. Many patients also feel like seeing colored halos around light.
How does it affect the cornea?
Cornea is the front portion of the eye comprised with three main layers –
· Epithelium – it acts as a barrier to protect the cornea from foreign particles like dust, debris and bacteria.
· Stroma – it builds upto 90% of the corneal thickness and is the middle layer comprising of collagens and other structural material. This layer provides, cornea the dome-shape and strength.
· Endothelium – is the single layer located on the descemet membrane to provide the appropriate balance of fluid in the cornea.
Initially the fluid may only build up during sleep and the vision may be hazy in the morning as soon the person gets up and gets better with the day. This is the first stage of the disorder and eventually if the condition worsens, and small blisters may be formed. During the second stage, the blisters gets bigger and breaks causing eye pain, changes in the shape of the cornea leading to other vision problems. The condition when the cornea swells and forms blisters in the front of the cornea is known as bullous keratopathy.
A bio-microscopic exam of the eye will reveal any abnormalities and the ophthalmologist may also suggest some additional examinations like pachymetry test to measure the corneal thickness, a specular microscopic examination to look at the thin layer of the cells that lines the back part of the cornea along with the visual acuity test.
What are the treatment options?
Depending on the severity and degree of the symptoms, treatment also varies. Treating with eye drops and ointments along with use of special salt solution that helps in removing the excess fluid out of the cornea works best to relieve the symptoms in the initial stages. If the sores become painful, surgical intervention is needed to create flaps over the sores to reduce pain.
In the case of endothelial dystrophy and ocular hypertension, doctor recommends glaucoma eye drops to reduce the intraocular pressure (IOP) as high eye pressure can damage the corneal endothelium and worsen the condition.
The only cure for FD is a corneal transplant.
Penetrating Keratoplasty was the only option for transplant that involved to surgically removing the damaged cornea, where patients had to be too careful to ensure the wounds don’t rupture even for years.
With advancements in the field of ophthalmology, development of laser ablations, corneal transplant techniques have revolutionized the patient recovery for better vision. Decemet’s Membrane Endothelial Keratoplasty (DMEK) replaces only the damaged endothelium of the cornea with a precision of upto one-twentieth of the actual corneal thickness. The tissue is carefully removed through a small incision, and the replacement donor tissue is rolled up, inserted and flattened out. Rather than stitches , the tissue is placed with an air bubble which helps in healing faster. Due to this the front surface of the cornea remains smooth and intact with DMEK which leaves the eye much stronger and less prone to accidental injury.