The Cornea And Types Of Corneal Irregularities
The cornea, which is the outermost layer of your eye, is clear and shaped like a smooth dome. Clear and acute vision depends upon having a healthy cornea. When you visit our eye care clinic in Mineola and Middle Village, NY, Dr. Melania Napolitano will assess the condition of your cornea, checking for corneal degenerations, corneal dystrophies, keratoconus, astigmatism, and corneal scarring. Read on for an explanation of different types of corneal irregularities that can affect your ability to focus properly.
Anatomy Of The Cornea
Your cornea contains no blood vessels, which makes it unique from most body tissues. So what protects the cornea against infection? Tears and the fluid found just behind your cornea, called the aqueous humor. Although the cornea appears to be just a transparent membrane, it actually has five layers – the epithelium, Bowman’s membrane, stroma, Descemet’s membrane, and endothelium – each of which plays an important role in ocular health.
A progressive thinning of the cornea characterizes keratoconus, which is the most common corneal dystrophy. Presently, it affects about one in every 2,000 Americans. This condition causes the middle region of the cornea to thin and bulge outward into a cone shape. The results can include be double or blurred vision, increased light sensitivity, nearsightedness, and astigmatism.
It is believed that genetics are a major determinant behind who gets keratoconus. At the beginning, we will typically treat it with eyeglasses or soft contact lenses, yet as the condition progresses, you will probably need specialty contact lenses (such as sclerals) for better vision. When keratoconus is very severe, a corneal transplant may be necessary.
This disease progresses gradually and generally affects both eyes. Most of time, people don’t realize there is a problem until they are over 50 or 60 years old. The deterioration of cells in the endothelium layer of the cornea causes Fuch’s dystrophy, which leads to corneal inflammation and thickening – thereby distorting vision. Typical treatment includes eye drops or ointments to reduce the swelling; in some cases, a corneal transplant is recommended.
The classic appearance of this disease is a lattice-like pattern of deposits in the stroma layer of the cornea. Amyloid, an abnormal protein fiber, composes these deposits, which increase over time and grow more and more opaque. Eventually, they merge and impair vision. Lattice dystrophy typically starts in early childhood. By age 40, some people with this corneal dystrophy have significant corneal scarring and only a corneal transplant can restore crisp vision.
This disease occurs when the epithelial basement membrane of the cornea develops abnormally and has folds in the tissue. These folds create gray shapes, sometimes with clusters of dots beneath them. People with this corneal dystrophy usually experience blurred vision, pain in the morning that lessens throughout the day, excessive tearing, light sensitivity, and a sensation that something is stuck in the eye.
The severity of map-dot-fingerprint dystrophy ranges; some patients will not suffer any symptoms, but others will have recurring painful erosions. Topical eye drops and ointments are generally frontline treatment, but when they are ineffective, a number of outpatient surgeries may be performed.
Pellucid Marginal Degeneration (PMD) is the most common corneal degeneration – not to be confused with keratoconus. Usually, it involves a clear, bilateral thinning in the peripheral regions of the cornea. The cause of this disorder is unclear, and it sometimes affects only one eye. Vision loss is the primary symptom, although eye pain can also present – albeit rarely (when corneal thinning leads to perforation).
During the early stages of this corneal degeneration, soft contact lenses often provide effective treatment, and rigid gas permeable lenses or specialty scleral contact lenses work later on. Numerous other types of corneal degeneration exist, some of which do not require treatment.
If you have any symptoms of corneal dystrophies, corneal degeneration, astigmatism, or corneal scarring, call our 20/20 Eyecare offices in Mineola and Middle Village to book an eye exam. Our eye doctor is experienced and knowledgeable about the diagnosis and treatment of corneal irregularities.