corneal infection, corneal dystrophy

Corneal Infection & Dystrophy

Corneal Infection & Dystrophy at Center for Sight serving Fall River, Massachusetts and greater Providence, Rhode Island

By Keegan Johnson, M.D.

About Corneal Infections
Corneal infections are a potential cause of discomfort and vision loss if not diagnosed and treated promptly. The outermost layer of the Cornea is called the epithelium. If it is damaged from trauma of any type, it is possible for bacteria, viruses or fungi to penetrate the Cornea and cause an infection. An infection of the cornea is called a Keratitis. Keratitis can cause a painful inflammation with a discharge, which if not treated quickly and appropriately, can lead to corneal erosion, corneal ulceration and corneal scarring. Corneal scarring results in a loss of corneal transparency and can require a corneal transplant in order to restore vision. In general, the deeper the corneal infection, the more severe the symptoms and the greater the potential for loss of vision. If he or she suspects that you have a corneal infection, the doctor will look for certain diagnostic signs to help him decide the best course of treatment for corneal infections. Sometimes this might be an antibiotic eye drop, an antifungal eye drop, an antiviral eye drop and sometimes it might even include a steroid eye drop to reduce the inflammation.

Herpes Zoster Keratitis (Shingles)
Herpes Zoster Keratitis is actually caused by the same virus that causes chicken pox, called Varicella-Zoster Virus. It is possible that after having chicken pox as a child, the Varicella-Zoster Virus remains in the nerve cells of your body in an inactive state. The Varicella-Zoster Virus can reactivate later in life and travel through the nerves in different parts of your body causing a painful blistering rash. If the Varicella-Zoster Virus travels to your head or neck it can affect the eye and thus cause a corneal infection.

It is critical to have the doctor diagnose this quickly as the infection can penetrate deeply into the cornea and it can cause scarring.  The infection can also result in a loss of corneal sensation, which can be permanent. It may be necessary to prescribe both oral medications and eye drops to try and resolve the infection and prevent serious damage from occurring.

It is possible for anyone who has been exposed to the Varicella-Zoster Virus to get shingles.  Individuals with suppressed immune systems or advanced age are most at risk for shingles. Further, corneal problems from shingles may occur many months after the facial shingles appear to have resolved. Therefore, if you have had facial shingles it is important for you to schedule regular follow up appointments.

Ocular Herpes and Herpes Keratitis
Ocular Herpes, or Herpes of the eye is caused by the Herpes Simplex Virus and is the most common causes of corneal blindness in the United States today. Up to 50% of people who have a single Herpes Simplex viral infection of the eye will experience a flare up or recurrence.  The virus often leads to irreversible scarring of the cornea.

Ocular Herpes may start as a painful sore on the eyelid or surface of the eye.  If left untreated, it may multiply and begin to destroy epithelial cells and progress deeper into the cornea. If the Ocular Herpes penetrates the deeper layers of the cornea and causes a Stromal Keratitis it may cause corneal scarring-so prompt diagnosis and treatment of Ocular Herpes is important.

It is estimated that 400,000 people in the United States have had some type of Ocular Herpes, with more than 50,000 initial and recurring cases being diagnosed each year. Of these, it is believed that 25% are the more severe form of Herpes Stromal Keratitis. It is important that if you have had any type of systemic Herpes infection you alert the doctor at your eye examination. The recurrence of Herpes Simplex eye infections is significant in that it appears to recur in about 10% of patients with one year, 23% of patients within two years and 63% of patients within 20 years of their initial infection. Sometimes a recurrence can be prompted by sunlight, stress, fevers or an unrelated eye injury.

The doctor may prescribe both oral medications and eye drops to try and resolve the infection and prevent serious damage from occurring. Prompt diagnosis and medication is key to preventing any vision loss.

About Corneal Dystrophies

Fuchs’ Dystrophy
Fuchs’ Dystrophy is a slowly progressive disease of the cornea that is found in both eyes and is slightly more common in women than men. While it is possible to observe Fuchs’ Dystrophy in people in their 30’s and 40’s, it usually does not compromise vision until people are in their 50’s or 60’s. The innermost layer of cells in the cornea, called the endothelium, is a single layer of non-regenerating cells. The endothelial cells are responsible for pumping water out of the cornea and helping to maintain the corneal transparency. In Fuchs’ Dystrophy, the endothelial cells prematurely weaken, making the endothelium less efficient in its pumping activity. This results in the cornea swelling and distorting vision. In its later phases, Fuchs’ Dystrophy is often associated with considerable pain as the epithelium blisters called “bullae.” These bullae can burst open and expose corneal nerves resulting in severe pain.

Early in the course of Fuchs’ Dystrophy patients will wake up with blurry vision that gets progressively clearer as the day passes. This phenomenon occurs because the cornea normally takes on water and swells during sleep.  A healthy endothelial pump is necessary in order to restore the cornea to a normal thickness. In Fuchs’ Dystrophy, the endothelium removes fluid from the cornea less efficiently.  As the Fuchs’ Dystrophy disease worsens, the vision does not clear. The Doctor will attempt to help reduce the corneal swelling each day with eye drops and ointments. However, when these measures fail to provide comfort and clear vision, it may be necessary to have a Corneal Transplant. Some patients with Fuchs’ Dystrophy that require surgery to restore vision may benefit from a new technique called Decemet’s Stripping with Endothelial Keratoplasty (DSEK).  This type of corneal transplant involves only the diseased portion of the cornea and is sutureless.

Map-Dot-Fingerprint Dystrophy
The outermost layer of the cornea, called the epithelium, is attached to an underlying basement membrane called Bowman’s Membrane.  Sometimes the epithelial basement membrane develops abnormally making it difficult or impossible for the epithelium to adhere properly to the basement membrane. If the epithelium does not adhere properly, Recurrent Corneal Erosions will occur. Recurrent Corneal Erosions are painful and cause the corneal surface to become irregular resulting in intermittent blurry vision along with the discomfort and foreign body sensation. Map-Dot-Fingerprint Dystrophy is also known as Epithelial Basement Membrane Dystrophy because it is caused by a lack of the healthy formation of the Basement Membrane. It affects adults between the ages of 40-70 and can sometimes begin earlier. As the name implies, its appearance is of a map of gray areas accompanied by opaque dots and fingerprint like whirls or lines.

The doctor can diagnose Map-Dot-Fingerprint Dystrophy during a routine eye examination in patients who do not have any noticeable symptoms. If treatment is required to control the pain for those patients who are symptomatic, the doctor may prescribe lubricating eye drops, patch the eye, apply a soft bandage contact lens or in more severe cases, scrape the cornea to attempt to achieve better adhesion of the epithelium. In some cases, the doctor may suggest that the best results can be achieved using Excimer Laser Phototherapeutic Keratectomy (PTK) to smooth the surface of the cornea.

Lattice Dystrophy
Lattice Dystrophy occurs as a result of the accumulation of abnormal protein fibers, or amyloid deposits in the middle cornea layer called the corneal stroma. If these deposits become dense enough they will become opaque and affect the corneal transparency so that vision is reduced. If these deposits occur under the outermost layer, the epithelium, they can cause recurrent erosions of the cornea, which can be painful and disturb the normal corneal curvature, effecting vision.

In instances where there are recurrent corneal erosions and pain, the doctor may prescribe eye drops, ointments and occasionally an eye patch or bandage soft contact lens.  Early Lattice Dystrophy seems to respond well to Excimer Laser Phototherapeutic Keratectomy (PTK) whereas more serious cases may require a corneal transplant.

Keratoconus is disorder of the cornea characterized by a progressive thinning of the tissue, and instability of the cornea. The cornea begins to bulge outward and become cone like. As the cornea shape deteriorates there is a significant change in the focusing power of the eye producing nearsightedness and astigmatism. Keratoconus usually affects both eyes. It may be possible to correct your vision with contact lenses. Unfortunately, for some patients, contact lens intolerance develops making a corneal transplant necessary.

If you are in need of a Corneal Transplant for Keratoconus, Dr. Johnson will take all the time necessary to explain the risks, benefits and likelihood of success in your particular situation. Please be assured that all of your questions will be answered so that you can make an educated and informed decision about your treatment options at Center for Sight.

About Other Corneal Conditions

Recurrent Corneal Erosion
Recurrent Corneal Erosion is a condition of the cornea whereby there is a poor attachment of the outermost layer of the cornea, the epithelium, to the underlying basement membrane layer, called Bowman’s Membrane. Patients who experience Recurrent Corneal Erosion may experience sharp pain, light sensitivity, tearing and watering of their eyes, a gritty sensation. Often this occurs upon awakening or rubbing the eyes. Recurrent Corneal Erosion is often a condition associated with Map-Dot-Fingerprint Dystrophy. The doctor may initially prescribe salt solution eye drops or ointment as the first line of treatment.  This medication helps the epithelium to adhere more firmly to Bowman's Membrane. Usually artificial tears are also recommended to keep the cornea moist. Sometimes, a soft bandage contact lens will be used to help the healing process.

Those patients who have a corneal dystrophy may require additional treatment.  This usually includes an in-office procedure at Center for Sight, where the epithelium is either gently removed, or microscopic "spot welds" are made on the cornea to encourage the epithelial layer to bond securely to Bowman's Membrane.

Patients, who continue to suffer from Recurrent Corneal Erosions despite the treatments described, may benefit from Phototherapeutic Keratectomy (PTK).  This involves removal of the superficial layer of corneal cells using the Excimer Laser to encourage proper healing.

A pterygium is a fleshy triangular growth of tissue on the cornea that may grow slowly throughout a person’s life.  Rarely, a pterygium can grow across the cornea and block the pupil. People who live in sunny climates where they are exposed to more sunlight and UV light are more prone to developing pterygia.

Pterygia may become red, swollen and inflamed.  Occasionally they need to be removed.  Removal of a pterygium is a surgical procedure that has recently undergone medical advances. Dr. Johnson uses a surgical technique called Amniotic Membrane Graft in order to prevent recurrences and obtain the best possible results for Pterygium surgery.

Stevens-Johnson Syndrome (SJS)
Stevens-Johnson Syndrome, also called Erythema Multiforme, is a disease of the skin that also affects the eyes. SJS causes blistering and painful lesions on the skin and mucous membranes throughout the body. If SJS is extreme it can cause conjunctivitis, corneal blisters and erosions or iritis-an inflammation of the iris. SJS can occur from an adverse reaction to drugs such as sulfa containing drugs or following viral infections. SJS can occur in any age group but is more common in those under 30 years of age.

Dry Eyes
Dry Eye Syndrome is a very common eye condition that can affect the cornea. If there is inadequate tear production, or rapid tear evaporation, symptoms of dry eyes may become present. These include a scratchy, dry, sandy or gritty feeling that can be accompanied by a stringy clear white discharge with noticeable pain and redness. Dry eye creates additional risk of corneal infection, as the tear film, which serves a protective mechanism and contains a number of antimicrobial components, is deficient.

For patients with mild to moderate dry eyes the first course of treatment may be to use unpreserved artificial tears or lubricant eye drops. Depending on the nature of your tear film deficiency, he may prescribe a specific type of artificial tear that has different characteristics in terms of salt content, viscosity or lubricity.

In addition, it may find it necessary to insert tiny “punctual plugs” into the openings of your tear ducts, in order to slow down or even stop the drainage of tears from the eye. Occasionally there are some cases that may not respond to the above sequence of treatment options because of some underlying low-grade inflammatory or infectious process. In these cases it may be necessary to also prescribe an oral antibiotic such as a tetracycline or an anti-inflammatory eye drop such as a corticosteroid eye drop.

If you suffer from moderate to severe dry eyes the doctor may prescribe Restasis eye drops, in addition to the other treatments can often help alleviate your symptoms. Restasis is an advanced type of cyclosporine eye drop that acts by blocking a specific type of inflammatory cell from entering the Lacrimal Gland, which produces normal tears. By reducing or blocking inflammation in the Lacrimal Gland, it functions much more effectively so that you can actually make more of your own natural tears and keep your eyes moist and lubricated.

If you or a family member or friend is in need of help for a corneal infection, dystrophy, problem or condition, please take a moment to request an appointment by calling Center for Sight in Fall River, Massachusetts at 508-730-2020.

Center for Sight is conveniently located for patients in need of evaluation and diagnosis of corneal infections and corneal dystrophies in Massachusetts or Rhode Island from Attleboro, Fairhaven, Fall River, Franklin, Mansfield, Marion, Mattapoisett, Medfield, Milford, New Bedford, North Attleboro, North Dartmouth, Norton, Oxford, Rehoboth, Somerset, Swansea, Taunton, Walpole, Whitinsville, Woonsocket, Providence, Smithfield, Westport, Lakeville, Dighton, Little Compton and Tiverton.