The cornea is the dome shaped, clear surface which covers the front of the eye. It is located within the eye's outer most layer. There are many different kinds of corneal disease, including the coreneal distrophies map-dot-fingerprint, lattice, and Fuchs' dystrophy. Other corneal diseases include keratoconus and ocular herpes. Diseases of the cornea are some of the most common types of eye problems.
There are many functions of the cornea. As the outermost layer of the eye, it can filter some of the most dangerous ultraviolet wavelengths of sunlight to prevent eye injury. Additionally, the cornea focuses and controls the entry of light into the eye by bending or refracting light rays to fall directly on the retina. It also functions as a protection mechanism by helping to shield the entire eye from harmful materials, such as germs. Five basic layers make up the cornea; they are the epithelium, bowman's layer, stroma, descemet's membrane, and the endothelium.
A corneal dystrophy is a condition in which the buildup of cloudy material causes parts of the cornea to lose some of its normal clarity. Corneal dystrophies are some of the most common types of corneal disease, typically involving at least one layer. There are many different types of this condition.
Fuchs' dystrophy is a corneal disease that generally progresses slowly. It occurs when the endothelial cells of the cornea break down. The endothelium becomes less able to function at pumping water from the stroma as an increasing number of endothelial cells deteriorate. Over the years, this may cause a distortion of vision if the cornea begins to swell. Tiny painful blisters may also start to surface on the the cornea as a result of this condition.
Lattice dystrophy is caused by the accumulation of protein fibers that are abnormal in the anterior and the middle of the stroma. The accumulated deposits may result in a lattice effect, created by overlapping dots that may appear comma shaped with branching filaments. As this corneal disease progresses, the accumulation may grow and gradually involve more of the stroma. Vision impairment may occur if the accumulated deposits result in cloudiness of the cornea.
Map-dot-fingerprint dystrophy is a disease of the cornea which can develop if the basement membrane, which serves as the foundation for epithelial cells, develops abnormally. This condition may cause blurred vision by changing the curvature of the cornea. Pain may result if nerve endings become exposed. Individuals with this condition may have slightly gray outlines on the epithelium that may have a map-like or dot-like appearance.
Another common types of corneal disease is keratoconus, which is a thinning of the cornea that can happen progressively. The disorder occurs when the middle of the cornea begins to bulge outward, gradually forming a rounded, cone-like shape. This change may cause an abnormal curvature in the cornea, changing its refractive power. The condition can also cause swelling and corneal scarring, which may result in visual distortion.
Ocular herpes is another disease that may affect the cornea. Herpes of the eye is caused by the herpes simplex virus. The condition usually results in painful sores that may appear on the eye surface and eyelids. Inflammation of the cornea may be caused by ocular herpes, which is one of the most common causes of corneal blindness.
Individuals encountering any abnormal changes in vision or eye behavior should consult an ophthalmologist. The doctor will be able to diagnose corneal disease and any other eye problems through a complete visual examination. Treatment for diseases of the cornea will vary by the individual and severity of the disease.
