What Is The Cornea? | Westlake Eye Specialists

What Is The Cornea?

closeup of mans eye

Your eyes are complex organs. They contain sensitive tissues like the retina, which detects light and sends it to your brain.

They also use tiny muscles to dilate your pupils, depending on how much light is available. The cornea, in contrast, is relatively simple.

But it is no less critical to our eyesight. Keep reading to find out what the cornea is and how it impacts your eyesight!

The Cornea Has Layers

The cornea is the clear tissue on your eye, covering your pupil like a window. It contains special cells and proteins and does not have any blood vessels.

If it contained blood vessels, they would cloud your vision and prevent the cornea from doing its job. Although only half a millimeter thick, corneas have three distinct layers.

Each corneal layer has its job. The outer layer is the epithelium. It acts as a barrier for the underlying layers, protecting them from foreign material.

It can also quickly absorb nutrients from tears, which the cornea needs due to its lack of blood vessels. The middle layer is the stroma.

The stroma is the thickest part of the cornea, making up almost ninety percent of its total mass. Its only job is to hold the cornea’s dome-like curvature and keep it strong.

Collagen, a solid and flexible protein, makes up the stroma. This composition allows the stroma to maintain the shape and strength of your cornea.

The bottom layer of the cornea is the endothelium. This layer is the thinnest, made up of only one layer of corneal cells.

The endothelium keeps the stroma above it hydrated. All three of these layers must be healthy for your cornea to function correctly.

The Functions of the Cornea

The cornea exists for two reasons. It acts as a barrier, and it focuses light entering your eye.

The cornea is a last line of defense against dust, dirt, germs, and other harmful matter that could enter your eye. Since it is thick and flexible, it can repel most invaders.

It can also filter most of the damaging UV light from the sun. Although you still need to wear UV-protected sunglasses to filter out the rest.

And, your corneas can heal from surface-level abrasions quickly. While the eye already has a lens behind the pupil, it only focuses a fraction of the light that enters the eye.

The majority of focal power in your eye is in your cornea. This is because its curvature is essentially a natural contact lens.

Common Corneal Problems

The cornea is quite durable compared to the rest of your eye. But it is still susceptible to injury, infection, and disease. 

The most common corneal issue is a refractive error. Refractive errors occur when the cornea is misshapen. This irregular shape results in poorly focused light and is why you need glasses. 

Your cornea can also experience something called corneal abrasions. Sometimes they can be too deep for the cornea to heal from and may lead to scarring that can disrupt vision.

You may also develop ulcers on your cornea from abrasion or infection. Another issue is an uncommon disease called keratoconus.

It affects your cornea, weakening it and causing it to bulge. Some treatments can mitigate the effects of keratoconus.

Keeping your cornea healthy is a vital part of taking care of your eyesight. Schedule an appointment at Westlake Eye Specialists in Austin, TX, to have yours examined!