Cornea and External Disease

Keratoconus

What is it?

Keratoconus is a type of eye disease which progressively thins the cornea and changes its shape. This disease changes the curvature of the cornea, resulting in irregular astigmatism and myopia which causes distortion of vision.

Symptoms

In the early stages, Keratoconus can cause the following:

  • Slight blurring
  • Distortion of vision
  • Increased sensitivity to glare and light

In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision.

Treatment

In the early stages, glasses or soft contact lenses can be used to correct the nearsightedness and astigmatism. As the disorder progresses, vision deteriorates, the cornea continues to thin, and rigid gas permeable contact lenses or collagen cross-linking (CXL) may be needed to correct vision. In advanced cases, a partial or full thickness corneal transplant may be necessary to replace the damaged cornea.

 

Cornea Scars and Dystrophies

What is it

Scars of the Cornea form as a result of trauma, infection and inflammation. Depending on how dense the scar is and its location for example, more central, scars can obstruct vision.

Corneal Dystrophies are group of congenital or hereditary disease for example, Granular or Anterior Basement Membrane dystrophy, which has lesions on cornea which can obscure vision or in the case of Fuch’s dystrophy (see below) result in a swollen, hazy cornea

Symptoms

Patients with scars and dystrophies may experience blurring/doubling of vision, poor contrast and visual quality and at times, pain.

Treatment

Depending on the condition and if it causes poor vision or pain, treatment in the form of eye lubricants, laser treatment to the cornea or in more severe cases, partial or full thickness cornea transplant may be required.

 

Psuedophakic Bullous Keratopathy (PBK)

What is it?

Like Fuch’s dystrophy, PBK is the resultant of a dysfunctional corneal endothelium resulting in swelling of the cornea.  However, in this case, it is a condition seen after cataract surgery where the endothelium decompensates after having had cataract surgery. It is an uncommon but known complication of cataract surgery.

Symptoms

In PBK, patients complain of worsening blurring of vision and in severe cases, the swollen cornea becomes painful as blisters cause by the swelling rupture leaving raw areas of exposed cornea.

Treatment

Treatment for PBK is managed very similarly to Fuch’s endothelial dystrophy.

 

Fuchs’ dystrophy

What is it?

Fuchs’ dystrophy is a slow progressive disease that usually affects both eyes and is slightly more common in women than in men. This disease occurs when the number of special cells on the back surface of the cornea (called endothelial cells) gradually deteriorates. As the cells diminish, it becomes less efficient at processing the water properly which makes up the corneal cell structure. This causes the cornea to swell and impair vision.

Symptoms

Signs and symptoms usually affect both eyes and may include:

  • Blurred vision especially in the morning
  • Seeing halos around lights
  • Sensitivity to light and glare

In the later stage, one might experience the following:

  • Painful tiny blisters on the surface of cornea
  • May lead to blindness if left untreated

Treatment

Eye medications

  • Concentrated salt eye drops or ointments can reduce the amount of fluid in the cornea, relieving symptoms of Fuchs’ dystrophy.

Exposure to warm, dry air

  • Using a blow dryer to evaporate excess fluid

Corneal transplantation