Common Types of Corneal Diseases
Keratitis generally refers to an inflammation of the corneal tissue. This can result from injury, such as a scratch, or wearing contact lenses for longer than intended. Bacterial infections are common in people who wear contacts, but infections can also be viral, parasitic, or fungal.
Ocular Herpes and Herpes Zoster
Herpes simplex virus 1, the same type of herpes that causes cold sores in and around the mouth, can also cause sores to develop on the surface of the cornea. The herpes zoster virus (which causes chickenpox) can reemerge as shingles and cause blisters or lesions to form on the eye.
The most common type of dystrophy, keratoconus results in progressive thinning of the cornea. Left untreated, the cornea will take on a cone shape and bulge outwards. Fuchs' and map-dot-fingerprint are two other types of corneal dystrophy.
Should I worry about my corneal health?
Family History and Contact Lens Use Are Two Major Predictors
Corneal dystrophies, of which there are more than 20 types, seem to run in families, though environmental and hormonal factors also appear to play a role. Contact lens wearers and patients who are prone to allergies and dry eyes are also at a higher risk of developing lesions or slight injuries to the surface of the eye. Certain types of herpes can also affect the health of your corneas.
How Do These Conditions Actually Damage the Cornea?
Contacts Can Cause Injury
Though some brands of contacts are designed for extended wear or can safely be worn during sleep, most are not. Contacts can harbor bacteria, scratch the surface of the eye, and block oxygen from the cornea, which further increases your risk of infection. In extreme cases, corneal ulcers may develop. Hard contacts can also cause trauma to the eye if they are worn incorrectly.
Viruses Can Create Inflammation
The virus that causes chickenpox can lie dormant in your nerve cells for years or even decades. When it is reactivated in the form of shingles, the virus can cause inflammation and scarring of the cornea. Ocular herpes can result in an infection that affects the eyelid, surface of the cornea, and eventually, deeper tissue within the eye.
Dystrophies Weaken the Structure of the Cornea
Though dystrophies vary significantly in their causes and effects, they are characterized by structural problems within the corneal tissue. Depending on the type, the corneal tissue may thin, swell, change shape, or develop abnormal folds, creating progressively blurred vision. Often, scarring and a buildup of material may also cloud the cornea.
What are some preventative measures I can take?
"Research into the mechanisms of blinding corneal disease continues to accelerate and exciting alternatives to surgery are appearing,"
- Dr. Stephen Tuft
Ophthalmologist at Moorfields Eye Hospital NHS Foundation Trust
Protect Your Eyes with Regular Eye Exams And Responsible Contact Lens Use
Know Your Family History
If you don't know already, learn whether keratoconus or any other corneal conditions have affected members of your family. This is important information to include in your medical records.
Schedule an Exam
Yearly eye exams focus on assessing the health of your corneas and other structures. Many corneal conditions progress free of symptoms until damage has occurred. Regular screenings allow for early intervention and often, more successful treatment.
Follow Lens Care Instructions
First, check that you're wearing your lenses no longer than intended. Do you slip up and sleep in them from time to time? Break the habit.Properly cleanse and disinfect lenses, and if you struggle to adhere to these instructions, consider disposable dailies or glasses.
How will my doctor test for corneal conditions?
A Visual Exam and Other Tests Can Evaluate Corneal Health
There are several tests your doctor may perform to determine the presence and severity of a corneal disease.
Slit Lamp Exam
To begin, your eye doctor will review your medical and family history, and examine your eyes and eyelids using a slit lamp microscope. Often, this is sufficient to confirm injury, such as a scratch on the cornea, or signs of infection.
Much like a topographic map of the earth, a corneal topography displays the elevation of different parts of the cornea.
Evaluate Corneal Shape and Thickness
In some cases, especially when corneal dystrophy is suspected, the doctor may use topography or keratometry (non-invasive imaging tests) to evaluate the shape and curvature of the cornea. Pachymetry is a type of test which measures the thickness of the cornea.
Assess Cells and Tear Film
Cultures and biopsies can also shed light on your corneal health. For example, a more detailed assessment might look at the health of the endothelial cells, the outermost portion of the cornea. Healthy tears also play a key role in protecting the cornea.
But what does treatment involve?
Treatment for Corneal Conditions Varies Widely Based on the Type
Infections due to conditions like herpes are typically treated with prescription drops and oral medications. Your doctor may recommend antibiotics, antivirals, antiparasitics, or steroids. Salty eye drops can also offset the effects of Fuchs' dystrophy and similar conditions.
Special Contact Lenses
Trauma due to injury or contact lenses is often treated with a special type of bandage lens. This protective measure allows the cornea to heal on its own. Keratoconus in its earliest stages can also be managed with special contact lenses, which maintain the proper shape of the cornea.
Some types of corneal dystrophy can be treated with phototherapeutic keratectomy, which combines ultraviolet (UV) light and laser technology to reshape the cornea.
In severe cases, healthy donor tissue is used to replace damaged corneal tissue. Advancements have resulted in more conservative transplant techniques with minimized risk of complications.
What can I do today?
Schedule an Exam to Protect Your Vision
Preventative screenings and prompt medical attention are the best ways to protect your eyes.If you have symptoms of an eye infection or pain, blurring, or other concerns, see an eye doctor right away. Otherwise, schedule an eye exam if you have not been in a year or more.
Want More Information?