Corneal Diseases

 

What is a cornea?

The cornea is the transparent, clear front part of the eye that covers the iris, pupil and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye’s total optical power. Various refractive eye surgery techniques change the shape of the cornea in order to reduce the need for corrective glasses or lenses.

Understanding Corneal Diseases

If a cornea becomes damaged through infection, injury or disease, the resulting corneal swelling, astigmatism or scars can interfere with vision by blocking or distorting light as it enters the eye. When there is deep injury to the cornea, the healing process may be prolonged, possibly resulting in a variety of symptoms including: pain, blurred vision, tearing, redness and extreme sensitivity to light.

Astigmatism

Astigmatism is a common imperfection of the curvature of the eye, causing distorted images. A cornea without astigmatism is round and spherical, like the surface of a basketball. Irregularities from corneal astigmatism can result in a football shaped surface. Astigmatism is usually temporarily corrected with glasses or contact lenses prescribed by your optometrist. However, there are surgical options to permanently improve vision by reducing astigmatism. This can be done with laser treatment applied to the cornea (LASIK, PRK, etc) or with the implantation of a Toric astigmatism-correcting intraocular lens during routine cataract surgery.

Keratoconus

Keratoconus means cone-shaped cornea. The cornea is involved in focusing images on the retina, which helps us see clearly. Normally, the cornea is round like a baseball, In keratoconus, the cornea becomes thin and cone-shaped like a football, which results in blurred and distorted vision. The curvature of the cornea becomes irregular, resulting in increasing myopia and astigmatism. Keratoconus is usually progressive and the cornea becomes more thin, steep, and irregular overtime.

Fuchs’ Corneal Dystrophy

Fuchs’ dystrophy is a disease of the cornea. It is when cells in the corneal layer called the endothelium gradually die off. These cells normally pump fluid from the cornea to keep it clear. When they die, fluid builds up and the cornea gets swollen and puffy. Vision becomes cloudy or hazy.

Fuchs’ dystrophy has two stages. In the early stage (stage 1), you may notice few, if any, problems. Vision is usually hazy in the morning but gets better throughout the day. This is because your eyes normally stay moist when they are closed during sleep. But when you are awake, the fluid dries normally.

With the later stage 2, vision remains blurry all day. Too much fluid builds up during sleep and not enough dries up during the day. Also, tiny blisters may form in the cornea. The blisters get bigger and eventually break open, causing eye pain.

People in their 30s and 40s may have Fuchs’ dystrophy but not know it. Vision problems might not appear until age 50 or later. Women are more likely than men to have Fuchs’ dystrophy. Family history of Fuchs’ dystrophy also increases your risk of developing it.

Your ophthalmologist will look closely at your cornea and measure its thickness. This is called pachymetry. They will also check for tiny blisters on the front surface of the cornea and drop-like bumps of the back surface of the cornea (guttae). Using a special photograph of your cornea, your ophthalmologist may count the cells in your endothelium.

There is no cure for Fuch’s Dystrophy. However, you can control vision problems from corneal swelling. Your treatment depends on how Fuchs’ dystrophy affects your eye’s cells.

Here are treatments for early Fuchs’ dystrophy:

  • Use an eye drop or ointment to reduce swelling of the cornea’s cells.
  • For very poor vision or scarred corneas, you may need a corneal transplant. This surgery could be one of two types:
Endothelial keratoplasty (EK): Healthy endothelial cells are transplanted into your cornea.
Full corneal transplant: The center of your cornea is replaced with a healthy donor cornea.

Your ophthalmologist will discuss what treatments are best for your condition.