Corneal Disease: 5 Common Types and Treatment Options

The cornea is a remarkable part of the eye that plays a vital role in your vision. This smooth, clear, and durable structure acts as the eye's outermost lens. Your corneas protect the eye from foreign materials such as dust, germs and harmful UV rays. The cornea also works to focus light so you can see clearly, accounting for about 70% of the eye's total focusing power.

The cornea's job is to focus incoming light—this is also called refraction—onto the lens, which is located inside the eye. The lens then refocuses the light onto the retina to convert into signals, which the optic nerve transmits to the brain to be interpreted as images. For you to see well, your cornea must remain clear and perfectly smooth to refract light properly. If refraction is not focused correctly due to corneal diseases or injury, your retina receives a distorted or blurry image.

What Are Corneal Diseases?

Corneal diseases include a wide range of disorders, including infections, degenerations, or inherited conditions. Corneal diseases can cause clouding, distortion, opaquing, scarring and eventually blindness.

Five of the better-known corneal diseases are:

• Fuchs' endothelial dystrophy
• Anterior Basement Membrane Corneal Dystrophy (ABMD)
• Pseudoexfoliation Syndrome (PXF)
• Bullous Keratopathy
• Keratoconus

1. Fuchs' dystrophy

Fuchs' dystrophy, also known as Fuchs' endothelial dystrophy, is a noninflammatory, hereditary eye disorder involving the cornea's innermost layer, the endothelium. This layer acts as a pump to remove excess fluid from the cornea, providing corneal transparency.

With Fuchs' dystrophy, the cornea starts swelling, causing glare, halos, and reduced visual sharpness in one or both eyes. In the advanced stages of Fuchs' dystrophy, tiny blisters may appear on the corneal surface, causing irritation and pain. The severe corneal damage from Fuchs' dystrophy can cause corneal blindness.

Fuchs' dystrophy affects 4% of Americans over the age of 40.¹ Characteristically, the disease begins after the age of 30 with symptoms presenting somewhat earlier in women than men.

Fuchs' dystrophy causes

• Autosomal dominant gene, meaning only 1 set of the gene is required to cause the eye disorder.
• Spontaneous gene mutation in someone without a family history.

Fuchs' dystrophy symptoms

• Decreased contrast sensitivity
• Perceptible glare with light or difficulty with nighttime driving.
• Decreased visual acuity
• Recurrent “gritty" feeling in the eyes
• Daily vision fluctuations, usually worse in the morning and improving by the end of the day.
• Vision deterioration on days with increased humidity or rain and improved on drier days.
• Occasional eye pain

Diagnosis of Fuchs' dystrophy

Fuchs' dystrophy is diagnosed during an eye exam. Your eye doctor will examine both of your eyes to look for signs of changes in your cornea. Fuchs' dystrophy diagnosis is primarily clinical, based on history and examination of the eye through a slit lamp, an optical microscope used to view the cornea in detail. Your eye doctor may also use a pachymetry to measure the thickness of your cornea as well as a confocal or specular microscope to photograph the corneal endothelium.

Fuchs' dystrophy treatment

For people with mild symptoms, hypertonic saline (sodium chloride) eye drops or ointments can improve vision by pulling excess fluid out of your cornea. Bandage contact lenses can help heal your cornea by delivering support to direct the epithelial cells to grow over the area of erosion.

Your doctor may recommend a full corneal transplant or an endothelial keratoplasty when vision is notably compromised, or chronic pain is present. A full corneal transplantation is a procedure where your damaged cornea is replaced with a healthy, donated cornea tissue. An endothelial keratoplasty (EK) entails transplanting corneal endothelial cells to replace your damaged corneal cells.

2. Anterior Basement Membrane Corneal Dystrophy

Anterior Basement Membrane Corneal Dystrophy (ABMD), also known as Map-Dot-Fingerprint Corneal Dystrophy, is the most common and treatable corneal dystrophy, affecting an estimated 6% to 18% of people.² ABMD is an eye disease affecting people of all ages and gender where the basement membrane beneath the corneal epithelium does not develop properly.

ABMD causes

The primary cause of ABMD is the underdevelopment or improper development of the basement membrane. The basement membrane anchors the epithelium but may have difficulty attaching to the stoma—the cornea's strong inner layer. This can result in the epithelium being more easily damaged and thus causing visual disturbances.

ABMD symptoms (H10)

• Many people with ABMD are asymptomatic, however, some people do have symptoms depending on the cause.
• Recurrent erosion. This occurs from recurrent scratches developing on the cornea. Since the epithelium is not anchored down well, even a little trauma can remove the epithelium. For example, when your eyelid crosses over a dry cornea upon awakening or by merely rubbing your eyes. Symptoms include eye pain, tearing, light sensitivity, blurry vision, double vision.
• Epithelium shift. Since the epithelium is not stuck down properly, it is common for the epithelium to shift and create folds or ridges, called Map and Fingerprint lines. Symptoms include blurry vision or double vision.

ABMD diagnosis

Diagnosis of ABMD involves a careful examination of the cornea to identify typical characteristic signs of the disorder with corneal topography. This diagnostic test calculates the smoothness and shape of the cornea's surface and may detect corneal anomalies. These distinct anomalies include either thick, unusual lines that may look like ridges (maps); small, grayish dots; or thin hair-like fingerprint lines in the corneal epithelium. These irregular contours signify changes in the corneal epithelial basement membrane.

ABMD treatment

If you have ABMD, your doctor may suggest an assortment of ABMD treatments. Mild ABMD cases without recurrent erosions may be treated with lubricating ointment and saline drops. Recurrent erosions may require bandage contact lenses and antibiotic ointment. To avoid recurrences, your doctor may recommend the application of nighttime lubricants.

Frequently reoccurring erosions despite medical treatment may benefit from surgical procedures including superficial keratectomy, phototherapeutic keratectomy, or stomal puncture to help the epithelium better adhere to the stroma.

Superficial keratectomy (SK) is a laser surgical technique that removes epithelium abnormalities or erosion to allow the epithelium to regrow smoother and improve vision.

Phototherapeutic Keratectomy (PTK) is similar to SK. It uses the excimer laser to remove the epithelium's deeper layers to create a stickier surface for the stoma to adhere.

A stomal puncture is an in-office procedure that creates tiny holes in the epithelium. The scars from these punctures help the epithelium to better adhere to the stroma.

3. Pseudoexfoliation Syndrome

Pseudoexfoliation syndrome (PXF or PEX) is a systemic disease that can affect your entire body. However, PXF manifests in your eyes' tissues through the ongoing accumulation of tiny flakes of amyloid-like material within the drainage structures between the iris and the cornea. When this flaky material obstructs your eye's drainage system, the pressure in the eye can increase and result in pseudoexfoliation glaucoma (PXF glaucoma). PXF glaucoma affects up to 50% of people with PXF.³

Pseudoexfoliation syndrome causes

• Age. PXF is an age-related disorder, affecting people aged 50 and over. Incidence increases with age.
• Gender. This disease is more common in women than men.
• Ancestry. PXF is more prevalent in people of European (especially Scandinavian) and Mediterranean descent.
• Genetics. If you have a family history of PXF glaucoma or carry the LOXL1 gene, you could be at higher risk of developing PXF.

Pseudoexfoliation syndrome symptoms (H15)

No real symptoms are associated with PXF, which is usually discovered during a routine eye exam. Symptoms are caused by the development of PXF glaucoma:

• Eye pain or pressure
• Blurry vision
• Seeing halos around lights

Pseudoexfoliation diagnosis

PXF diagnosis is made during an eye exam using a slit lamp to identify tiny flakes of PXF material in the front of the eye. Your eye doctor may also use a tonometer to check the eye's pressure; eye dilation to check the retina and optic nerve; and gonioscopy to check the drainage angle.

Pseudoexfoliation treatment

There is no PXF treatment required unless you have developed PXF glaucoma. PXF glaucoma treatment may include lowering the intraocular pressure with eye drops, laser surgery or glaucoma surgery.

4. Bullous Keratopathy

Bullous Keratopathy is a corneal imbalance caused by fluid entering the cornea from a dysfunction in the endothelium, the cornea's inner cellular layer. When this swelling develops, fluid-filled blisters form on the corneal surface, affecting your eyesight.

Bullous Keratopathy causes

• Illness or external trauma causing damage to the corneal endothelial cells.
• Congenital dystrophies of the endothelium, such as Fuchs' dystrophy.
• Surgical traumas from cataract or glaucoma surgery.

Bullous Keratopathy symptoms

• Fluid-filled blisters on the corneal surface from corneal swelling.
• Burst blisters can cause severe pain, light sensitivity, blurred vision and a recurrent “gritty" feeling in the eye.

Diagnosis of Bullous Keratopathy

A Bullous Keratopathy diagnosis is based on the characteristic appearance of a swollen, cloudy cornea with surface blisters. During the examination, your eye doctor may use a slit lamp and apply eye drops containing a yellow-green dye called fluorescein. The fluorescein briefly stains the cornea's damaged parts, enabling the doctor to view the damaged areas not otherwise detectable.

Bullous Keratopathy treatment

For people with mild symptoms, hypertonic eye drops, or ointments are used to draw fluid from the cornea. Your doctor might also prescribe drugs to lower pressure in the eye. Soft contact lenses may be used to reduce pain and act as a bandage for your cornea to heal. For more severe cases, a full corneal transplantation or EK may be warranted.

5. Keratoconus

Keratoconus is a rare, noninflammatory disorder where the cornea becomes thin and changes shape. With Keratoconus, the usually round cornea becomes weak and bulges like a cone. This new cone shape causes the light entering your eyes to be out of focus on the retina. Consequently, vision becomes blurry and distorted, making it challenging to do daily activities such as reading or driving. Keratoconus occurs in 1 in 2,000 Americans.⁴

Keratoconus causes

• Having a family history of Keratoconus increases your chance of developing the disorder.
• Eye trauma from rubbing your eyes or wearing hard contacts.
• Specific conditions, like allergies, asthma, Down syndrome, Ehlers-Danlos syndrome and sleep apnea.
• A group of rare eye diseases that affect the retina known as retinitis pigmentosa.

Keratoconus symptoms

• Glare or sensitivity to light
• Double vision
• Poor night vision
• Decreased visual acuity
• Frequent eye prescription changes
• Progressive nearsightedness
• Irregular astigmatism

Diagnosis of Keratoconus

Your eye doctor can diagnose Keratoconus by slit lamp examination and observation of central or inferior corneal thinning. Additional testing through corneal topography helps to map and identify early Keratoconus and allows for progression tracking. Additionally, the thinnest zone on your cornea can be measured with ultrasound pachymetry.

Keratoconus treatment

Treatment for Keratoconus may initially require glasses or soft contact lenses. However, as the disease progresses, your eye doctor may prescribe rigid gas permeable contact lenses. For more severe cases of Keratoconus, full corneal transplantation or corneal cross-linking may be necessary.

Corneal cross-linking uses a unique form of ultraviolet light to stimulate riboflavin eye drops on the cornea. This treatment stabilizes the cornea and decelerates the disease advancement.

CareCredit Credit Card Financing for Corneal Disease

Whether you're paying for eye surgery or getting an eye exam, the CareCredit credit card can help you pay for care where your insurance leaves off.* Use our Acceptance Locator to find a vision specialist near you that accepts CareCredit. Continue your wellness journey by downloading the CareCredit Mobile App to manage your account, find a provider on the go and easily access the Well U blog for more great articles, podcasts and videos.

In addition to vision care, you can also use your CareCredit credit card for dentistry, cosmetic, pet care, hearing, health systems, dermatology, pharmacy purchases, spa treatments, and so much more within the CareCredit network. How will you invest in your health and wellness next?

Expert Reviewer

Dr. Alexandra Chebil, M.D., F.R.C.S.C.

Dr. Alexandra Chebil is a board-certified ophthalmologist with the Lasik Center Medical Group in Newport Beach, California, who has more than 25 years of experience with refractive surgery and noninvasive facial aesthetic procedures. She was one of the first ophthalmologists to perform LASIK, and has successfully performed more than 70,000 procedures.

Author Bio

Susan Paretts is a freelance writer with 18 years of experience covering health and wellness, pet care and more. Her work has been published by the American Kennel Club, Bayer Animal Health, Elanco, LIVESTRONG.com, Care.com, City National Bank, The San Francisco Chronicle, Chewy and more.