Keratoconus

What is a Keratoconus?
Keratoconus is characterized by the thinning of the cornea and irregularities of the cornea’s surface. The cornea is the clear, outer layer at the front of your eye. The middle layer is the thickest part of the cornea, mostly made up of water and a protein called collagen. Collagen makes the cornea strong and flexible, and helps keep its regular, round shape. This healthy cornea focuses light so you can see clearly. With keratoconus, the cornea thins and bulges into an irregular cone shape, resulting in vision loss.
What are the Causes?
Several things may have a link to the condition:
- Family history: If someone in your family has this condition, you have a greater chance of getting it yourself. If you have it, get your children’s eyes checked for signs starting around age 10.
- Age: It usually starts when you’re a teenager. But it might show up earlier in childhood or not until you’re 30. It can also affect people 40 and older, but that’s less common.
- Certain disorders: Studies have found a connection between keratoconus and systemic conditions such as Down syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, and retinitis pigmentosa.
- Inflammation: Inflammation from things like allergies, asthma, or atopic eye disease can break down the tissue of the cornea.
- Eye rubbing: Rubbing your eyes hard over time can break down the cornea. It can also make keratoconus progress faster if you already have it.
- Race: One study of more than 16,000 people with keratoconus found that people who are Black or Latino are roughly 50% more likely to get it than people who are white.
What are the symptoms?
Many keratoconus patients are unaware they have the disease. The earliest symptom is a slight blurring of vision or progressively poor vision that is not easily corrected.
Other symptoms of keratoconus include:
Glare and halos around lights
Difficulty seeing at night
Eye irritation or headaches associated with eye pain
Increased sensitivity to bright light
Sudden worsening or clouding of vision
How is keratoconus diagnosed treated?
The doctor needs to measure the shape of your cornea. There are different ways, but the most common is called corneal topography. The doctor snaps a photo of your cornea and checks it closely. Children of parents with keratoconus should have one every year starting at age 10.
Treatment of keratoconus focuses on the correction of vision and depends on the stage of the disease.
Early Stages
Current treatment for keratoconus includes glasses in the earliest stages to treat nearsightedness and astigmatism. As keratoconus progresses and worsens, glasses are no longer capable of providing clear vision, and patients need to wear a contact lens, usually a hard contact lens.
Intermediate Stages
Progressive keratoconus can be treated by corneal collagen cross-linking. This one-time, in-office procedure involves the application of a vitamin B solution to the eye, which is then activated by ultraviolet light for about 30 minutes or less. The solution causes new collagen bonds to form, recovering and preserving some of the cornea’s strength and shape.
While the treatment cannot make the cornea entirely normal again, it can keep vision from getting worse and, in some cases, may improve vision. The procedure may require the removal of the thin outer layer of the cornea (epithelium) to allow the riboflavin to penetrate the corneal tissue.
Cross-linking was approved as a treatment for keratoconus by the FDA in April 2016, after clinical trials showed that it stopped or produced a mild reversal in bulging of the cornea within three to 12 months after the procedure.
Advanced Stages
Corneal ring. With severe keratoconus, a standard contact lens may become too uncomfortable to wear. Intacs are implantable, plastic, C-shaped rings that are used to flatten the surface of the cornea, allowing improved vision. They may also allow a better contact lens fit. The procedure takes about 15 minutes.
Corneal transplant. In a corneal transplant, a donor cornea replaces the patient’s damaged cornea. Corneal transplants are often performed on an outpatient basis and take about an hour to complete. Vision usually remain blurry for about three to six months after the transplant, and medication must be taken to avoid transplant rejection. In almost all cases, glasses or a contact lens are necessary to provide the clearest vision after transplant surgery.