The Cornea's Role
The cornea performs many important functions for clear vision. It provides the optical power necessary to see fine details, focus on a single object and read. By changing its shape, the cornea also plays a role in regulating the size of the pupil or opening that lets light into your eye. Without a functioning cornea, you’d see very little detail. In fact, vision may be reduced to the point of blindness.
The Anatomy of the Cornea
The cornea is the transparent part of the eye and is made up of five layers. The five layers are known as the epithelium, Bowman’s layer, the corneal stroma, Descemet’s membrane and endothelium.
Fuchs' Corneal Dystrophy
Fuchs’ Corneal Dystrophy is a condition associated with advancing age that is often hereditary. It develops in people in their 20s and 30s, but most commonly occurs after the age of 60. Fuchs’ is the fluid buildup of the cornea, which causes it to swell and thicken. This causes damage to tiny nerve endings at the back of your eye and results in blurry vision and halos around lights.
Keratoconus is a non-inflammatory eye disorder that typically affects people in their teens and 20s. In addition to distortion, patients with keratoconus have severe irregular astigmatism that can cause blurry or wavy vision along with light sensitivity from the cornea’s progressive thinning. Although this condition has been thought to be genetic, it has recently been attributed to environmental factors.
Dry Eye Syndrome
Dry eye syndrome is one of the most common eye disorders. It occurs when a person doesn’t produce enough tears or lacks sufficient moisture to keep the cornea healthy and smooth. Without a smooth surface, vision will be blurred and can be accompanied by a stinging sensation in the eyes. Fortunately, most people respond to treatment that replaces the lost moisture of their eyes with regular use of over-the-counter artificial tears or ointments.
Pinguecula and Pterygium
Pinguecula is the yellowish buildup of tissue, which usually occurs in people who spend time in sunny climates. It’s not harmful but may represent irritation or clouding of the cornea. Pterygium, on the other hand, is a growth of fleshy tissue within the cornea that originates from an overgrowth of blood vessels or other ocular surface cells. It occurs in areas of the eye that are chronically exposed to the sun because it is derived from these light-exposed structures. Pterygia can spread across the cornea, causing blurry vision and blockage of light.
The cornea is extremely sensitive to infection because it has no blood vessels to help fight off pathogens. There are many different types of bacteria, fungi and viruses that can cause blindness if left untreated.
Antibiotics, ointments and artificial tear lubricants are some of the more common nonsurgical therapies. For conditions that affect vision, eye doctors may prescribe glasses or contact lenses to correct errors in refraction (nearsightedness, farsightedness or astigmatism).
Laser surgery is the most common surgical therapy for corneal diseases. The most common type of surgery is Phototherapeutic Keratectomy (PTK), which involves the use of lasers to remove layers of corneal cells one at a time until the desired shape is reached. Other surgeries, such as DSEK and DMEK, are also effective in treating keratoconus or other conditions that affect the back of the cornea.