Keratoconus: Symptoms, Causes & Treatments

Published on 06/21/2023
keratoconus symptoms causes treatments

Keratoconus is a diagnosis indicating the eye’s cornea is thinner and has changed shape from round to more of a cone-like curve. The cornea is an essential part of the eye’s anatomy. Its job is to focus light on an area at the rear of the eye - called the retina. The light focuses on a single point when the cornea is healthy and round. However, a conical shape causes the light to focus on more than one point, leading to issues with vision and requiring treatment.

Like most issues affecting eye health and vision, an eye exam is the only way to diagnose and treat keratoconus accurately.

What Is Keratoconus?

Research shows that keratoconus is partially genetic since at least 10% of all patients with keratoconus have a parent who had it too. However, there are other risk factors associated with developing keratoconus, many of which mean it can be avoided with careful attention and healthy lifestyle choices.

Keratoconus takes some time to develop, as the cornea is weakened by a person’s actions, choices, or environment. The thinner the cornea becomes, the more challenging time it has maintained a strong, round curve. As a result, it begins to weaken and collapse, causing it to become more like a cone - visible in close-up eye profile images.

While keratoconus doesn’t hurt, it does cause vision loss due to resulting blurred vision. In most cases, people with keratoconus are also diagnosed with something called astigmatism.

Symptoms Of A Cone-Shaped Cornea

In most cases, you won’t know you have keratoconus until it causes vision problems. The most common symptoms of the condition are:

  • Blurred vision
  • Distorted vision (straight lines may appear wavy or bent)
  • Worsening vision (typically by adolescence or in the 20s to early 30s)
  • Double vision with one eye and potentially even while wearing glasses
  • Noticing halos around lights at night (which contributes to night blindness)
  • Increased light sensitivity or glare
  • Inability to wear contact lenses (most lenses are designed to fit a round, rather than cone-shaped, curvature, so some patients can’t wear them depending on the degree of the conical shape)

Even if you don’t notice the slow-developing vision changes associated with keratoconus, we’ll catch them during your eye exam.

Causes And Risk Factors

We mentioned that genetics play a role in whether or not you’ll develop keratoconus. However, other factors put you at higher risk for developing the condition.

Excessive eye rubbing

We can’t emphasize enough the importance of avoiding the urge to rub your eyes. Rubbing your eyes causes microabrasions across the surface of the eye. Most of the time, you don’t know they’re present, but these scratches continue to weaken and thin the cornea over time. Eventually, it can thin the cornea, leading to keratoconus. 

If you are a chronic eye rubber, or you notice a child does, schedule an eye exam to rule out eye strain as the result of any vision loss. Instead, learn more about how to safely massage and soothe your eyes, which prevents eye damage but provides necessary relief.


As this post goes to press, we’re right smack dab in the middle of allergy season. Naturally, if you suffer from chronic or seasonal allergies, you’re more likely to rub your eyes to relieve the itch and irritation. Similarly, the pollutants that cause allergies may be scratching the surface of your eye without you knowing it, creating the same recipe for thin corneas as excessive eye rubbing.

Speak to your physician and optometrist about the best ways to manage allergies year-round, which can protect your eyes from cornea thinning.

Eye strain

Similarly, eye strain or fatigue also increases the urge to rub your eyes. The better rested you are, and the more disciplined you are about taking screen breaks throughout the day, the less strained your eyes will be.

Certain genetic or health conditions

There are also certain genetic or medical conditions associated with keratoconus, like Down syndrome, sleep apnea, asthma, Leber congenital amaurosis, and various connective tissue disorders (Ehlers-Danlos syndrome, Marfan syndrome, or brittle cornea syndrome).

Treatment Options For Patients

Treatment for keratoconus depends on the general cause, your health, and the severity of the keratoconus. Mild cases are corrected using eyeglasses. Sometimes contacts can work, but that depends and may require a bit of trial and error to determine which type of lenses are best for you.

In more moderate to severe cases of keratoconus, treatment options may also include:

Rigid, gas-permeable lenses

Sometimes soft contacts can work, but more often the cornea’s shape requires hard contacts to compensate. These are carefully fitted and the optometrist will work with you to ensure they’re comfortable and facilitate clear, focused vision. These contacts are not disposable and require patients to honor the cleaning and care instructions for comfort and to prevent the risk of infection.

Laser surgery

We may be able to use laser surgery to restore a more regular cornea shape. Laser surgery is used to treat a range of eye conditions, including astigmatism, farsightedness, cataracts, and more. However, in some cases, the cornea is too thin, so it isn’t an option for everyone.

Collagen cross-linking

Some patients benefit from a procedure called collagen cross-linking. We use special drops that have vitamin B2 and then expose the eyes to ultraviolet light. This encourages the strengthening of the corneal layer. It prevents the cornea from bulging any further.

Implantable ring segments

There are different-sized ring segments that can be inserted into the cornea. This may help with the fitting of contact lenses. Or, in other cases, we combine this treatment with another corneal cross-linking surgery, preventing the worsening of the corneal bulge.

Cornea transplants

Corneal transplants, using the corneas from a donor cadaver, are also used to treat keratoconus. This is only recommended in severe cases. The cadaver corneal tissue is used to replace all or a portion of your own.

Eye To Eye Family Vision Care Treats Keratoconus

We treat keratoconus daily here at Eye to Eye Family Vision Care. Our goal is to find the least invasive method that gains the greatest outcome for our patients. Contact us to schedule your consultation.