Nov 11, 2019 • All articles LASIK & vision facts

Everything you need to know about keratoconus

Being diagnosed with keratoconus can be overwhelming. This hereditary degenerative condition can seriously impact both your level of vision and quality of life. However, with a variety of treatments available and plenty of research being done, keratoconus can be well managed.

What is keratoconus?

Keratoconus is the thinning of the cornea – the clear dome-shaped outer surface of your eye. This eventually causes the cornea to bulge in a cone-like shape. Your cornea is made up of (among other things) many collagen fibres. Think of keratoconus as you would a sweater whose fibres have become loose, causing it to lose its shape.

This condition can affect one or both eyes and can cause a variety of symptoms (depending on how severe it is), such as blurred vision, double vision, trouble seeing despite wearing glasses or contact lenses, as well as dizziness, headaches, and sensitivity to light.

Another important effect which isn’t physical is the impact on quality of life. A study involving data collected from 16 centres in the U.S. over eight years showed that even patients who were able to achieve 20/20 or 20/30 vision with glasses or contact lenses felt that keratoconus impacted their quality of life. For example, some had to miss days of work or, at the end of the day, felt all they could do was go to bed.

Who gets keratoconus?

Usually affecting people around ages 10-25, keratoconus occurs in about one in 1,000 people and affects men and women fairly equally.

While there is no specific known cause for keratoconus, there are conditions that might put you at a higher risk of getting it. According to a seven-year study, certain autoimmune diseases such as rheumatoid arthritis, ulcerative colitis, Hashimoto’s thyroiditis, asthma, and irritable bowel syndrome might be tied to keratoconus.

Other risk factors include atopic conditions such as allergies and eczema, lupus, Marfan syndrome, sleep apnea, and some mental health conditions like schizophrenia.

While some people theorize that frequent eye rubbing (such as when one is seeking to get relief from itchy eyes) could contribute to the changing shape of the cornea, this theory is not conclusive.

Does keratoconus lead to blindness?

No, keratoconus does not typically lead to blindness. It usually progresses for ten or more years after inception but with proper monitoring and the wide variety of treatment options available, blindness is easily avoidable.

However, there is a concerning temporary adverse effect called acute corneal hydrops. This is caused by a tear in the Descemet membrane (a layer of your cornea), causing fluid to leak through into the cornea and a sudden decrease of vision. However, with proper attention, it usually resolves on its own within a few months.

Similar conditions

There are other conditions that might sometimes be confused with keratoconus. A few examples are:

Astigmatism: This is when the cornea is of an irregular shape rather than being perfectly round, without actual thinning of the cornea
Lenticonus and lentiglobus: These are both deformities of the lens of the eye, as opposed to the cornea
Pellucid marginal degeneration (PMD): Sometimes misdiagnosed as keratoconus, PMD is when the cornea thins in specific areas on the sides (not center). It usually occurs in a person’s 20s to 50s and is not thought to be hereditary
Keratoglobus: Like PMD, it is also a thinning of the peripheral cornea, but is usually present at birth

Can keratoconus be cured?

While there is no cure for keratoconus, there are many treatments available and it can be well managed over the course of a person’s life. The most common treatments are:

Glasses or soft contact lenses: In the very early stages of keratoconus, these may help manage symptoms such as blurry vision. However, they cannot stop the progression of the disease.
Rigid gas permeable (RGP) lenses: These types of contact lenses can slightly mask the irregular shape of the cornea, as they do not mold to it, but maintain their shape. However, for this same reason, they can also feel uncomfortable.
Scleral lenses: These differ from other contact lenses because they are larger and rest on the white of the eye, vaulting over the cornea, instead of touching it. They often feel more comfortable than RGP lenses and can prevent eye dryness, while also allowing the eye to breathe more. In some people, no type of contact lenses, including scleral lenses, are a good fit due to scarring, contact lens intolerance, or a cornea that is too thin.
Intacs: These are very small plastic inserts that are implanted into the eye in order to re-shape the cornea to improve vision. The downside to Intacs is that they cannot stop the progression of keratoconus and they can be dislodged if ever there is trauma to the eye.
Corneal Cross-Linking (CXL): This procedure is designed to re-strengthen the bonds of the collagen fibres in the cornea in order to stabilize or improve the shape of the cornea. This can improve vision and even allow the person to wear contact lenses, where they may have previously been unable to due to the lenses not fitting properly. CXL is done on an outpatient basis and involves the application of riboflavin (vitamin B2) drops and UVA light to the cornea; this encourages the collagen to cross-link, or form bonds. And not to worry, the dose of UVA light is very low and the thickness of your cornea is measured beforehand to make sure it can tolerate the exposure. At LASIK MD, we also offer topography-guided PRK (T-PRK), often performed in conjunction with CXL. T-PRK is an advanced technology that allows surgeons to view a highly-detailed map of the eye, providing a guide for extremely precise treatment.
In severe cases, keratoplasty (corneal transplant from a donor) or keratoprosthesis (transplant of an artificial cornea) can be performed. Keratoprosthesis is usually reserved for those who experienced one or more failed donor transplants.

Looking forward: innovative treatments

While there are many treatments currently available, keratoconus is still widely being studied and there are many exciting new developments going on. Here are just a few:

Instead of performing an entire corneal transplant, one study placed donor tissue from the second layer of the cornea (Bowman layer) onto the middle layer. The outcomes were promising, with 90 percent of participants’ disease progression halted. The study was small, however, and would need to be repeated with a larger group, but the less-invasive nature of the procedure, lack of post-operative complications and the positive outcomes could be worth looking into.
A group of researchers at The University of Auckland looked at using eye drops with low levels of steroids with growth factors to stimulate collagen production in order to strengthen and stimulate the cornea. Conducting their research on sheep with keratoconus, they are hoping to move to clinical trials on humans.
In Japan, ophthalmologist Kohji Nishida is using re-programmed stem cells, called induced pluripotent stem cells, to repair corneas. His first patient had improved vision and he is continuing his study on at least three more patients.
Similar to the idea of the CXL procedure, researchers are looking into an even less invasive technique to flatten the bulge of corneas in keratoconic eyes. In a small study, instead of having riboflavin and UVA light applied to the eye, patients with keratoconus ingested 400 milligrams of riboflavin and were exposed to 15 minutes of natural sunlight each day. The patients reported no adverse reactions and the results were promising.

It’s important to take any changes in your eyes or vision seriously and have regular eye exams. If you have been diagnosed with or suspect keratoconus, come see us to see how we can help.