What keratoconus is and how it affects the eye
Keratoconus is an eye disease where the clear front part of the eye (the cornea) gets thinner and starts to bulge outward. A normal cornea is dome-shaped, but keratoconus makes it more cone-shaped. This can cause blurry vision and other eyesight changes.
Keratoconus usually affects both eyes, but it can affect each eye differently.
Does keratoconus get worse over time?
Keratoconus usually does get worse, but not in every case.
When it progresses, the changes often happen over many years. For some people, the changes happen more quickly.
Early diagnosis is important. Starting treatment early can help slow down or even stop the disease from getting worse.
Most people with keratoconus are diagnosed during their teens or 20s. It often stops progressing before age 40.
Does keratoconus cause blindness?
While keratoconus can affect your eyesight in different ways, it will not make you blind. With the right care, most people with keratoconus can keep good vision their entire lives.
Severe keratoconus can impair your vision. This is when an eye doctor might recommend surgery to help you see better.
How common is keratoconus?
Keratoconus is uncommon but not rare.
Eye doctors now have better tools to help them diagnose very mild or early keratoconus. Because of this, they’re learning that the disease might be more common than they thought.
Right now, studies estimate that 1 in 400 to 1 in 2,000 people in the U.S. have keratoconus, but it’s more common in some other countries.
Symptoms of keratoconus
Keratoconus symptoms affect your eyesight in ways that aren’t always easy to correct with glasses.
Vision symptoms can include:
- Blurry vision (usually the first symptom)
- Double vision
- “Ghosting” of light and images
- Straight lines look bent or wavy
- Sensitivity to light
- Problems seeing at night
Keratoconus can also cause these eye symptoms:
- Itchy eyes
- Red eyes
- Eye pain (rare)
Symptoms can get worse as keratoconus progresses. You might find that:
- You’re getting more nearsighted (distant objects look blurrier).
- Your vision prescription changes more often, and things may still look a little blurry, even with new glasses or contacts.
- You can’t comfortably wear contact lenses anymore.
What causes keratoconus?
Researchers aren’t exactly sure why keratoconus happens. Studies have shown that it’s probably caused by a combination of factors that vary from person to person.
This means that, many times, an eye doctor can’t find a clear reason why someone has keratoconus.
Risk factors
Some factors may raise your chances of developing keratoconus, such as:
- A parent with keratoconus
- Certain genes in your DNA (scientists are still trying to find the exact genes)
- A habit of rubbing your eyes a lot
- Eye allergies, eczema, asthma and other conditions that can make you rub your eyes more
- Sleep apnea
- Ehlers-Danlos syndrome, Marfan syndrome and other connective tissue diseases
- Down syndrome
- An eye-related condition, like floppy eyelid syndrome, retinitis pigmentosa or retinopathy of prematurity
Most people with these risk factors won’t get keratoconus, but regular eye exams are still important. They give your eye doctor a chance to catch changes early so they can start treatment.
Does rubbing your eyes cause keratoconus?
Most researchers agree that eye rubbing alone doesn’t cause keratoconus if your corneas are healthy.
However, if your corneas are already weaker or at risk for keratoconus, then rubbing your eyes could “trigger” the disease or make it worse.
Diagnosis and testing
An eye doctor can diagnose keratoconus during a comprehensive eye exam.
Your eye doctor will ask about your personal and family medical history during the exam. Then, they’ll use tests like these to check for keratoconus:
- Slit-lamp test – The doctor uses a special microscope with a bright light to look closely at your cornea.
- Corneal mapping – Tests like corneal topography and tomography make a “map” of your cornea. This helps the eye doctor find thinning or other early changes before they can be seen.
- Keratometry – A test that measures the curve of your cornea to see how irregular its shape is.
- Pachymetry – A test that measures the thickness of your cornea to see if it’s gotten thinner.
- Visual acuity test – A standard eye chart test that checks how clearly you can see letters at different distances.
Monitoring keratoconus
Since keratoconus can change over time, your eye doctor will ask you to schedule at least one checkup every six to 12 months. That way, they can:
- Repeat tests to check your vision and the shape of your cornea.
- Make sure your glasses or contact lens prescription is up to date.
- Adjust your treatment plan if they need to.
If you have keratoconus and your symptoms change, talk to your eye doctor — don’t wait until your next eye exam.
Treatment options for keratoconus
There isn’t a cure for keratoconus, but treatment can improve your vision and help protect it for the future.
Your eye doctor can recommend the best option based on your eyes and symptoms.
Prescription glasses and soft contacts for mild keratoconus
In the early stages of keratoconus (or if it’s mild), prescription glasses or soft contact lenses for astigmatism might be enough to help your vision. This is because the cornea hasn’t changed shape very much.
These options can help you see more clearly, but they won’t slow down the disease.
Since the cornea can change over time, people with keratoconus may need new prescriptions more often than usual.
Corneal collagen cross-linking for early or progressing keratoconus
Corneal collagen cross-linking (CXL) is a treatment that uses special eye drops and ultraviolet (UV) light. The vitamin B2 (riboflavin) in the eye drops reacts with the UV light to strengthen the weakened cornea.
CXL can slow down keratoconus and help some people avoid a corneal transplant. It may also help flatten the cornea, which can make it easier to wear contact lenses.
CXL works best in the early stages of keratoconus, but it’s sometimes used in more advanced cases. An eye doctor may not recommend it if the cornea is already very thin or scarred.
Specialty contact lenses for moderate keratoconus
Your eye doctor might suggest wearing specialty contact lenses that hold their shape on your cornea better.
These are called rigid gas permeable (RGP) lenses. They’re also known as “hard” contacts because they’re firmer and less flexible than regular soft contacts.
An eye doctor might recommend scleral lenses if other lenses aren’t a good fit.
Scleral lenses are also rigid, but they’re bigger than RGP lenses. The edge of a scleral lens rests on the sclera (the white of your eye) without touching the cornea itself.
Corneal inserts for moderate or advanced keratoconus
Intacs are small, curved inserts placed in your cornea to help flatten its shape. They can improve your vision and make it easier to wear contact lenses.
Corneal transplants for moderate or advanced keratoconus
If you have severe symptoms or a very thin cornea, you may need corneal transplant surgery (keratoplasty) to see more clearly.
During this surgery, the ophthalmologist removes the damaged cornea and replaces it with a healthy one from a donor. Your doctor can choose from different procedures, depending on your eyes.
Your vision should start to get better within a few weeks of surgery, but full recovery can take several months or longer.
Most corneal transplants are very good at helping people with advanced keratoconus see better.
New treatments and research for the future
Researchers are exploring new ways to find and treat keratoconus, such as:
- Stronger or faster versions of CXL
- New cornea implants and other surgical techniques
- Genetic research to help diagnose keratoconus earlier
These are still being tested and developed, but they could give people with keratoconus more treatment options in the coming years.
READ MORE: 10 different treatment options for keratoconus
Daily habits and lifestyle tips
You can take steps every day to help slow keratoconus and protect your vision. For example:
- Don’t rub your eyes (this is very important).
- Wear protective eyewear during high-risk sports or activities.
- Wear sunglasses with 100% UV protection.
- Avoid long periods of eye strain.
- If you wear contacts, make sure they fit well and the prescription is up to date. Let your eye doctor know if something feels uncomfortable or unusual.
- Practice good contact lens hygiene.
Don’t forget to schedule at least one complete eye exam every year or as often as your eye doctor recommends.
Living with keratoconus
Keratoconus might make you feel anxious or frustrated sometimes, but you’re not alone. With the right care, most people with keratoconus can keep good vision and live full, active lives.
If you ever feel overwhelmed, talking with other people who have keratoconus can help. Patient support groups or online communities, like the keratoconus groups on Facebook and Reddit, are good places to start.
Patients and their families can also call the toll-free National Keratoconus Foundation “warmline” for support, questions and referrals.
