Ocala Eye features the latest technology used in the diagnostic testing for corneal abnormalities and diseases. Our cornea specialist, Peter J. Polack, M.D., F.A.C.S. can determine the cause and specify treatments for diseases affecting the cornea. If necessary, advanced corneal transplant techniques such as DSAEK can be used to restore lost vision.
The cornea is the eye’s outermost layer. It is the clear, dome-shaped surface that covers the front of the eye and it helps direct light rays towards the lens for focusing. Unlike most tissues in the body, the cornea contains no blood vessels to nourish or protect it against infection. The cornea must remain transparent to see well, and the presence of even the tiniest abnormal blood vessels can affect vision. The preservation of your sight is our top priority and your Ocala Eye physician can compile a complete picture of your eye health using:
- Corneal topography
- Orbscan corneal mapping
- Specular microscopy
- Corneal pachymetry
- Wavefront™ aberrometry
Corneal ulcers are infections of the cornea. They are most often associated with soft contact lens use or trauma to the cornea. Prompt identification of the pathogen (usually bacteria) and aggressive treatment is needed to limit damage to the eye. In some cases, infection of the cornea can lead to infection inside the eye (endophthalmitis) and, rarely, loss of the eye. Early testing possibly including a diagnostic scraping or biopsy may be required to determine the cause of the infection. Our corneal specialist works with microbiologists and pathologists at nearby laboratories.
Fuchs' dystrophy is a hereditary condition which occurs when endothelial cells gradually deteriorate without any apparent reason. It is one of the most common conditions requiring a corneal transplant. Although it can be seen in people as young as their 30s or 40s, it is typically seen later in life. As more endothelial cells are lost over the years, the endothelium becomes less efficient at pumping water out of the cornea resulting in swelling. In the early stages of the Fuchs’ dystrophy, this swelling can cause cloudy vision; eventually, in later stages, this can lead to pain and severe visual impairment.
A unique symptom of Fuchs’ dystrophy is foggy vision in the morning which clears as the day progresses. In this stage, symptoms may be lessened with saline drops or ointment. As the disease progresses, however, the fogginess lasts most of the day. When drops can no longer clear the vision, and it interferes with daily activities, a patient may need to consider a corneal transplant.
A Pterygium is a pinkish, triangular-shaped tissue growth on the cornea. Pterygia are more common in sunny climates and in the 20 to 40 age group. Studies suggest where sunlight is strong, wearing protective eyeglasses, sunglasses, and/or hats with brims may help reduce the incidence of pterygium.
Because a pterygium is visible, many people want to have it removed for cosmetic reasons. It is usually not too noticeable unless it becomes red and swollen from dust or air pollutants. Surgery to remove a pterygium is not recommended unless it affects vision, causes significant discomfort, or if the ophthalmologist notes that it has a suspicious appearance. If a pterygium is surgically removed, it may grow back, particularly if the patient is less than 40 years of age and does not reduce risk factors, such as direct sun exposure or chronic irritation from allergies or a dusty or dirty work environment.
Herpes of the eye, or ocular herpes, is a recurrent viral infection that is caused by the herpes simplex virus and is the most common infectious cause of corneal blindness in the United States. The herpes simplex virus is present in most humans and many people manifest the virus as fever blisters around the mouth. Why only some people develop herpes in the eye is unknown.
Ocular herpes can produce a painful sore on the eyelid or surface of the eye and cause inflammation of the cornea. Prompt treatment with anti-viral medications helps to stop the herpes virus from multiplying and destroying epithelial cells. Repeated flare-ups can lead to significant scarring and possibly blindness. In some cases, a corneal transplant may be required.
To schedule a consultation for corneal care, contact Ocala Eye today.
To treat diseases and other problems associated with the cornea, we use the following surgical procedures.
DSAEK now offered at Ocala Eye
Individuals in the central Florida area who need a cornea transplant in order to restore their vision now have another option for treatment at Ocala Eye. DSAEK (pronounced de-sak) is a transplantation procedure that is associated with quicker visual recovery, a smaller incision, and much less astigmatism than the standard corneal transplant technique known as penetrating keratoplasty (PKP).
Standard cornea transplant method (PKP)
PKP has been the standard of care for many years and most physicians are very familiar with the postoperative care. It provides excellent vision with the appropriate glasses or contact lenses in most cases. It does require frequent visits to the doctor to measure the cornea, prescribe glasses, and take care of the stitches.
The cornea is a transparent dome on the front of the eye. Corneal edema (swelling) produces decreased vision due to loss of transparency of this normally clear tissue. The swelling arises from a loss of endothelium, a thin layer of cells found on the back surface of the cornea. These cells are not capable of dividing or repairing themselves. The only treatment for visually significant corneal swelling is to replace these cells.
Until recently, the only way to replace endothelial cells was to perform a full thickness corneal transplant procedure called penetrating keratoplasty (PKP), requiring complete removal of the patient's cornea and replacement with a donor cornea. Unfortunately the wound can take years to heal so the new cornea is sutured in place with very fine stitches left in place indefinitely to maintain strength and stability. After the operation, it usually takes several months to years to obtain your best vision. It is very difficult to predict the final curvature of the cornea; so after surgery, glasses or contact lenses are required in the majority of cases. If the stitches break, there may be a feeling like having sand in the eye, and removal of the stitches may change the curvature of the cornea requiring new glasses. In addition, the broken stitches may produce a corneal infection requiring the use of antibiotics to treat the infection and can rarely lead to graft failure.
Recently a new procedure has been developed to replace the endothelial cells that does not require a full thickness replacement of the cornea. In the DSAEK procedure (Descemets' Stripping Automated Endothelial Keratoplasty), a thin piece of donor corneal tissue containing the endothelial cells and posterior stroma is inserted through a small incision on the side of the eye. This tissue adheres to the back surface of the original cornea and clears the corneal swelling.
The advantages of DSAEK are that extensive stitching of the cornea is not required and the eye heals more quickly. Although glasses will still be required after the operation, they may be much thinner as the power of the eye after surgery is much more predictable. In addition, the surgery is safer as the new cornea is inserted through a small incision rather than a complete opening of the front part of the eye reducing the chance of a devastating hemorrhage during the surgery or infection afterwards. Because a smaller incision is used, the eye is left stronger so that if it is inadvertently struck there is less likelihood of a serious injury.
The main disadvantage of the DSAEK procedure is that the new endothelium is manipulated more directly than in a full thickness corneal transplantation, potentially producing more damage and possibly resulting in graft failure. There is a 10% chance that the new tissue will not adhere properly requiring repositioning, or in less than 1% of cases, re-operation. The long-term survival of this tissue has not been fully studied. The cornea is also left much thicker than the original due to the addition of tissue to the posterior aspect of your current cornea. This may make it more difficult to follow glaucoma.
In order to make the new tissue stick onto the back of the old cornea, an air bubble is used to completely fill the front part of the eye for an hour after surgery. After that time the air is partially released and left overnight. During the first twenty-four hours, it is important to stay on your back as much as possible to keep the air bubble positioned correctly, anchoring the new tissue in place. When you are seen the next day, the position of the new tissue will be checked. It may be necessary at that appointment or the next appointment one week later to reposition the new tissue by placing a new air bubble. Once the tissue sticks, it remains in place, so the most critical post-operative period is the first six weeks.
After the DSAEK procedure
After DSAEK, the vision clears faster than the full thickness corneal transplant operation and you can return to your normal activities within two weeks with the exception of swimming. Like full thickness corneal transplantation, eye drops are required for at least a year and more often for the rest of your life to prevent graft rejection, where the body recognizes the tissue as being foreign and reacts against it. Fortunately graft rejections are very unusual (less than 10% of cases) and if they do occur, can be treated successfully in the majority of cases with frequent eye drops and occasionally oral medications. The cornea is a privileged site where powerful immunosuppressive medications such as those associated with heart or kidney transplants are rarely necessary to prevent graft failure.
Ocala Eye is pleased to bring this new procedure to central Florida and we look forward to working with this new option for improving our patents' vision.