The cornea is the eye’s built-in protector. It is clear and, along with the white of the eye (the sclera), provides a barrier against dirt, germs, and other things getting into your eye. It even screens out some of the ultraviolet radiation that would otherwise enter your eye.
The cornea also plays a key role in your vision quality. Your cornea bends light as it enters your eye; the accuracy of this bending is how well you see objects at different distances.
The cornea can be affected by various diseases and conditions. The common causes of these are infections, trauma, degenerative disorders, autoimmune disorders, nutritional deficiencies, growths, ectasia (thinning), and allergies. At Longwood Eye & LASIK Center we provide treatment and surgery for many of these diseases.
What Corneal Diseases and Conditions Does Eye & Lasik Treat?
What Are the Signs and Symptoms of Corneal Disease?
Problems with the cornea often show themselves with redness around the cornea and/or corneal cloudiness. These are common symptoms:
- Visual impairment, such as blurred or cloudy vision
- Severe pain in the eye
- Sensitivity to light
- Headaches, nausea, fatigue
How Does Longwood Eye & LASIK Center Diagnose Corneal Diseases?
We employ a variety of tests and tools to diagnose diseases/problems with your cornea. Beyond a careful visual exam of your eyes and eyelids, and a review of your medical history, we’ll check the cornea with a slit lamp microscope. The slit lamp allows us to examine the anterior segment and posterior segment of the eye, including the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and the cornea.
Additional testing may include:
- Topography and keratometry to study the shape of the cornea
- Pachymetry to measure the thickness of the cornea
- Microscopy to assess the health of the endothelial cells and identify infections
- Tear film assessment
Blepharitis is an inflammation of the eyelids. This usually occurs when tiny oil glands located near the base of the eyelashes become clogged. This irritates the eyes, making them red. Several diseases and conditions can cause blepharitis, and it can be chronic and difficult to treat. Fortunately, it doesn’t usually cause damage to your vision.
How We Diagnose Blepharitis
An examination of your eyelids, looking for clogged glands is the first diagnosis step. We may swab your skin to sample the oil and crust on your eyelid. This can give us an idea what’s behind the inflammation, be it an allergen, bacteria, or fungi.
How We Treat Blepharitis
Washing the eyes in warm water with a focus on the eyelids and using warm compressions can often open these clogged glands. Beyond that, we may use prescription medications:
- Medications to address the infection — Antibiotics applied to the eyelids can resolve bacterial infections.
- Medications to control inflammation — Steroid eyedrops and ointments can control inflammation.
- Treatments for underlying conditions — Blepharitis caused by other issues such as rosacea, seborrheic dermatitis, and other diseases can be treated by targeting the disease to resolve the blepharitis.
- Medications that target the immune system — Topical cyclosporine is a calcineurin inhibitor that can relieve this condition.
As the name implies, dry eye is a condition that occurs when your eyes aren’t providing adequate lubrication for your eyes. Your tears may be either of poor quality or you simply may not produce enough of them. Dry eye makes your eyes sting and burn. The eyes will become red, sensitive to light, and it can feel as if there is something in the eyes. Treatment often may be ongoing.
How We Diagnose Dry Eye
To diagnose dry eye we will perform a comprehensive eye exam first. From there we may:
- Measure the volume of your tears — This is done using the Schirmer test. Blotting strips are placed under your lower eyelids. After five minutes we measure the portion of the strip that has been soaked by your tears.
- Determine the quality of your tears — We next test the surface condition of your eyes. Using special dyes, we look for staining patterns on the cornea. We also measure how long it takes your tears to evaporate.
How We Treat Dry Eye
Treating dry eye may be as simple as providing artificial tears for the patient to use. In other cases, we may have to manage another condition that is causing your dry eye. Other treatments look to improve tear quality or stop your tears from draining too quickly.
- Prescription medications — Medications we may use range from those to reduce eyelid inflammation or control cornea inflammation, to tear-stimulating drugs and eye inserts that dissolve and release lubrication.
- Surgery — We may partially or completely close your tear ducts by inserting tiny silicone plugs.
- Light therapy and eyelid massage — Directing intense pulsed light, followed by eyelid massage, can be effective for severe dry eye.
If the cornea has been damaged, a cornea transplant, clinically known as keratoplasty, may be necessary. A cornea transplant can restore vision, reduce pain, and improve the appearance of the damaged cornea.
Many conditions can merit a cornea transplant:
- Thinning of the cornea
- An outwardly bulging cornea
- Fuchs’ dystrophy
- Cornea scarring from infection or injury
- Clouding of the cornea
- Swelling of the cornea
- Corneal ulcers
Cornea Transplant Surgery
The most common type of corneal transplant is called penetrating keratoplasty. Your Longwood Eye & LASIK Center surgeon uses an instrument known as a trephine, to cut a small circular disc from the diseased or abnormal cornea. Then precisely measured donor cornea tissue is placed in the hole. This is known as a full-thickness corneal transfer. It is a very successful surgery with low risk.
Anterior Stromal Micropuncture
Recurrent corneal erosion syndrome (RCES) is a common disorder involving the corneal epithelium (the outer layer) and the epithelial basement membrane. This condition is characterized by repeated breakdown of the epithelium and causes moderate to severe eye pain and can lead to corneal scarring and vision changes. The recurrent part of the title means this can happen even multiple times each week, where the epithelium erodes, regrows, and erodes again. RCES can be caused by an old injury or abrasion of the eye, or an inherited eye disease.
How We Treat RCES
There are three layers in the front of the cornea. The outer layer, the epithelium, is constantly replacing its cells, not unlike our skin. The second layer behind that is the Bowman layer, which is the layer the epithelium should stick to. Behind the Bowman layer is the stroma layer, the main thickness of the cornea.
In an anterior stromal micropuncture, your Eye & LASIK surgeon takes a specialized needle and makes tiny punctures through the epithelium, through the Bowman layer, and just barely enters the stroma. These punctures create very small scars that help improve the adhesion from the epithelium and decrease the recurrence of erosions.
This is usually done on the areas of the cornea outside the center, to avoid too much scarring in the center of the vision.
Pterygium is an eye condition that affects people who spend a great deal of time outdoors. It involves the growth of pink, fleshy tissue on the conjunctiva (white part of the eye), usually on the side toward the nose. The cause of pterygium is excessive exposure to ultraviolet light, dust, wind, sand, and humidity. Those characteristics lead to its colloquial name, surfer’s eye.
Pterygium is a non-cancerous growth that can develop slowly over time and may not present a threat to the patient’s eyesight, unless it covers the pupil of the eye. Only if it interferes with the patient’s eyesight is surgery needed. This is because pterygium tends to regrow.
How Is Pterygium Surgery Performed?
At Longwood Eye & LASIK Center, we may use one of two methods for pterygium surgery. The goal is to stop or at least thoroughly hinder the regrowth of pterygium.
Pterygium Excision with Graft
This is the procedure we use to remove the abnormal growth on the sclera. Prior to adding the graft, this surgery, known as the bare sclera technique, resulted in a hole on the surface of the conjunctiva that made it likely to regrow pterygium again in the future. But now, a tissue graft taken from the underside of the eyelid corrects this problem.
The patient is under local anesthesia for this surgery — both light oral sedation and local anesthesia on the eye itself. Then the pterygium is excised along with a portion of the surrounding conjunctival tissue. Next, the area where the growth was removed is then scraped with a blade and an abrasive burr to remove any remaining vascular attachments that may remain where the growth was. Then the graft is taken and placed on the excision site. It is placed with an adhesive mixture, usually thrombin and fibrinogen.
Amniotic Membrane Grafting
As in the above method, the pterygium is excised along with a portion of the surrounding conjunctival tissue. Instead of a graft, freeze-dried human amniotic membrane tissue is placed onto the bare sclera. We place and adhere this to the sclera with fibrinogen.
There is conflicting research on whether the likelihood of regrowth is better or about the same with the amniotic membrane method or the excision with graft method. Both have a dramatically lower recurrence, however, than the bare sclera technique.
What Are the Risks of Corneal Surgery?
Cornea transplants, stromal micropuncture, and pterygium surgeries are considered to be relatively safe procedures. However, there are risks. These include:
- Clouding of the lens
- Later cataract development
- Increased intraocular pressure (inside the eye)