Cornea and External Diseases

The cornea is the transparent tissue on the front of your eye. It serves as a barrier to protect your eye from dirt and other substances. The cornea also acts as the eye’s outermost lens and provides 2/3 of the eye’s total focusing power. There are many conditions that can affect the transparency and shape of the cornea. Some common cornea and external diseases include:

• Corneal abrasion: A scratch or injury to the cornea that causes pain or blurred vision
• Fuchs Dystrophy: A genetic condition where a build-up of fluid causes the cornea to swell.
• Keratoconus: A degenerative condition that changes the shape of your cornea and causes it to thin and bulge outward
• Keratitis: Inflammation of your cornea that can be noninfectious or infectious

Cornea and external diseases of the eye can have different causes, depending on the condition. These include:

You have a higher risk of some corneal diseases if you:

Symptoms of cornea and external diseases vary based on the condition. Most get worse over time.

These may include:

Some cornea and external diseases don’t have symptoms. You need a comprehensive eye exam to get a diagnosis.

If you’re having any of the symptoms above, see your eye doctor. They will discuss your medical history and do a comprehensive eye exam.

This typically includes a:

• Fluorescein eye stain test: Your doctor puts dye in your eye and shines a light on it to check for damage to your cornea.
• Slit lamp exam: Your doctor dilates your pupils and uses a special microscope with a bright light to look at the layers of your eyes.
• Map of the cornea: A photographic image of the cornea shape and curvature
• Ultrasound measurement of the thickness of your cornea

If your doctor thinks you have a corneal ulcer, they may also take a small tissue sample or culture.

After your doctor reviews your test results, they will recommend next steps. Your treatment depends on your condition.