A healthy cornea is needed for an overall healthy eye. It is an integral part of the eye that plays a key role in your vision. As light enters your eye, it gets refracted by the cornea’s curved edge, which helps determine how well your eye can focus on objects far away and up close. Corneal diseases and conditions can affect your eye health, and your vision.

If your cornea is damaged by an injury, infection, or disease, the light might be blocked or distorted upon entering your eye, therefore affecting your vision.

What is the Cornea?

In order to learn about the conditions that affect the cornea, it helps to understand what the cornea is. Similar to the windshield of a car or the crystal on a wristwatch, the cornea is a clear structure that makes up the central outer surface of the front of the eye. It forms a dome-like chamber over the iris (the colored part of the eye), pupil (black, circular opening in the center of the iris), and lens— all of which are inside the eye. And just like a windshield, if the cornea becomes cloudy or opaque, it can significantly limit a person’s ability to see. The same happens if the cornea becomes warped in shape due to a variety of factors.

Common Corneal Diseases and Conditions

All of these common corneal diseases and conditions can greatly affect your vision:

  • Dry eye
  • Fuch’s dystrophy (and other corneal dystrophies)
  • Keratoconus or corneal ectasia
  • Ocular allergy
  • Herpes simplex keratitis
  • Corneal abrasion
  • Corneal ulcers
  • Other contact lens-related disorders

If you have been diagnosed with a corneal disease or condition or think you may have a corneal problem, contact our office in St. Louis and schedule an appointment with our cornea specialist, Dr. Geoffrey Hill.


Dry Eye

Dry eye occurs when the eye does not produce tears properly, or when the tears are abnormal and evaporate too quickly. In addition to this, inflammation of the surface of the eye may occur along with dry eye. If left untreated, this condition can lead to fluctuating vision, ulcers, pain, irritation, red eyes, scars on the cornea, and some loss of vision.

Symptoms can include: stinging or burning of the eye, pain, and redness, uncomfortable contact lenses, and a sandy or gritty feeling as if something is in the eye. There are numerous causes of dry eye.

Treatment may be different for each individual with dry eye depending on the cause.

Fuchs Dystrophy

Fuchs dystrophy is an inherited genetic disease that affects approximately 15 million Americans. It causes premature loss of corneal endothelial cells—which form the innermost layer of the cornea—and leads to progressive vision loss due to corneal clouding and swelling.

The definitive treatment of Fuchs is a corneal transplant surgery to replace the abnormal endothelial cells.


Keratoconus is a connective tissue disorder that affects teens and young adults. Patients have progressive thinning and steepening of the cornea, which causes the shape to become more “cone-like” than round. This leads to distortion and blurring of vision. Some patients with keratoconus develop scarring that severely limits their vision.

There are a broad range of treatments for keratoconus depending on the severity of the disease, including medications, specialty contact lenses, and surgical procedures to restore vision.

Corneal crosslinking is the only treatment that can halt or slow the progression of corneal shape changes that occur in keratoconus. Crosslinking is an FDA-approved treatment for progressive keratoconus and can be performed in the office. After undergoing corneal crosslinking to prevent progression or worsening of keratoconus, patients may be candidates for vision correction with glasses, contact lenses, or some surgical procedures.

Ocular Allergy

Eye allergies are one of the most common ocular surface diseases in eye care, affecting about 40 percent of Americans of all age groups. Ocular allergy is an inflammatory reaction of the surface of the eye to particles (allergens) in the environment, such as pollen, ragweed, or pet dander.

While ocular allergies are intermittent, often non-sight-threatening complaint, they are far from trivial. If severe enough, blood vessels and scarring can occur across the cornea leading to decrease in vision which may only be repairable by surgery.

Herpes Simplex Keratitis

Herpes simplex keratitis is an infection of the cornea that is caused by the Herpes Simplex virus. Treatment typically involves topical therapy, antiviral drugs, or a combination of these. The infection usually heals without damaging the eye, but the more severe infections can lead to ulceration, corneal hypoesthesia, permanent scarring, and decreased vision or blindness. HSV keratitis is known for its recurrences and is a major cause of blindness worldwide.

Corneal Abrasion

A corneal abrasion happens when something cuts, scratches, or scrapes your cornea. In some cases, abrasions are caused by the direct impact of a sharp object or foreign body, but they can also be caused by small, airborne particles, such as dust, sand, or flying debris from woodworking or weed trimming. Even fingernails can cause corneal abrasions, especially in babies with uncut nails.

Symptoms include a constant feeling of something in your eye, tearing, redness, pain (especially when you open or close your eye), sensitivity to light, and blurred vision. Corneal abrasions can be irritating and often painful. They usually heal quickly, however, and do not cause any lasting problems. In rare cases, corneal abrasions can become infected. If you need emergency eye care for your corneal abrasion, don’t hesitate to contact us immediately.

Corneal Ulcers

A corneal ulcer is considered more severe than an abrasion because it consists of an infection within the substance of the cornea. Most cases of corneal ulcers are caused by bacterial infections that invade the cornea in association with contact lens use or following eye injury, trauma, or other damage.

Symptoms of a corneal ulcer are typically obvious to the patient, especially if the ulcer is deep. Because the cornea is very sensitive, corneal ulcers tend to be very painful. In addition to this, redness, discharge, and burning can occur. Corneal ulcers may manifest themselves as a white spot on the cornea, so examine the area in a mirror to look for such symptoms.

Treatment for corneal ulcers—such as antibiotics, antiviral, or antifungal medications—might need to be aggressive to prevent vision loss and blindness. Patients with corneal ulcers or symptoms of this kind should seek medical attention with an ophthalmologist immediately.

Contact Lens-Related Disorders

Contact lens disorders, such as contact lens allergy, over-use, and corneal ulcers are common problems affecting the cornea and ocular surface. Symptoms include irritation, tearing, and redness with contact lens wear. This problem can often be improved with a thorough eye exam and sometimes a simple contact lens re-fitting.

Contact our St. Louis Corneal Disease Specialists!

Dr. Geoffrey Hill is a cornea specialist trained in the diagnosis, management, and surgical treatment of a range of conditions affecting this integral part of the eye, including corneal diseases and conditions. Schedule an evaluation today with Dr. Hill and the rest of the team at Hill Vision Services to see what we can do for you!