Keratoconus, which literally means “cone-shaped cornea,” is the most common corneal dystrophy in the US, affecting 1 in every 2,000 people. This noninflammatory, progressive thinning of the cornea causes the front part of the eye to bulge outwards, resulting in a pointed shape like the end of a football. There is no known significant geographic, cultural, or social pattern to the prevalence of keratoconus; it occurs all over the world and affects all races and genders equally.
The cornea is the eye’s outermost layer, covering and protecting the colored iris and black pupil of the eye. The lack of blood vessels gives the cornea its clear, transparent appearance and allows it to act as a window that is primarily responsible for refracting, or bending, the light coming into the eye. Together with the lens, the cornea focuses the light onto the retina at the back of eye, which converts the image we see into electric signals that are sent to the brain. Consequently, keratoconus can have a very detrimental effect on visual acuity.
The earliest symptoms of keratoconus include slight blurring, distortion, and increased sensitivity to light due to the abnormal shape of the cornea. Double vision in one eye and “ghost” images, or the appearance of several images when looking at an object, may also occur. As the cornea becomes more cone-shaped, keratoconus can progress for 10-20 years and then slow or stabilize. In more severe cases, the protruding shape of the cornea can even cause a tiny crack to develop and the cornea to swell. Unfortunately, keratoconus may be mistaken for other eye conditions such as cataracts or even a mere change in prescription, so it is important to get your eyes checked by an optometrist! An eye professional can detect changes in your cornea that may not be so obvious by just looking in the mirror. The main sign that an optometrist will sees is an abnormally high curve or steepening of your cornea. One of the diagnostic tools your optometrist will use is a corneal topographer.
Keratoconus often occurs during the onset puberty; it is most prevalent in teenagers and young adults in their 20’s. The cause, however, remains unclear, but is most likely multifactorial. Studies have suggested a correlation between keratoconus and factors such as certain eye diseases, like retinitis pigmentosa, and systemic diseases, like Down syndrome. Several studies have also reported an association between keratoconus and trauma, such as eye rubbing. Just as continuously rubbing your hand can cause a callous, rubbing your eye can also cause a change in the appearance of the tissues.
There are multiple treatment options available for patients with keratoconus. In the earliest stages, glasses and soft contact lenses can be used to correct the nearsightedness and astigmatism due to the abnormal curvature of the cornea. As the condition becomes worse, rigid gas permeable (RGP) lenses may be a better option. While the idea of a “hard” contact lens may sound scary, there are many advantages to these contact lenses. RGP lenses allow oxygen to flow through the lens to the cornea even though they are made of an extremely durable plastic material. In addition, they can be designed specifically for the curvature of your cornea and retain their shape, leading to clearer, crisper vision. There is even a reduced risk of eye infections as compared to soft lenses, which contain water and can harbor bacteria. In the most severe cases of keratoconus, a corneal transplant may be necessary. This surgical procedure replaces the cornea with healthy donor tissue, leading to improved, stable vision. While the success rate is 90%, most transplant patients do still require glasses or contacts after surgery.
A recent breakthrough with patients with keratoconus is a procedure called corneal crosslinking. This will treat the cornea and prevent further steepening and degrading by hardening the cornea.
We highly encourage you to visit an optometrist every year for an eye exam; it is always important to check for conditions such as keratoconus to ensure you love the way you see!
Serving the communities of Costa Mesa, Irvine, Newport Beach, Tustin, Santa Ana, Huntington Beach, and Fountain Valley. Schedule a visit with Dr. Valerie Lam or Dr. Thanh Mai to learn more. Our optometry practice is located in Costa Mesa at 3151 Airway Ave. Suite J2, Costa Mesa, CA 92626 and we offer vision therapy and orthokeratology services.
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