Keratoconus, corneal ectasia, KC, KCN, cornea transplant - A State of Sight #22

Keratoconus is a progressive disease that distorts the normally dome-shaped cornea into the shape of a cone. This may cause blurred vision and astigmatism. Isaac Porter, MD explains keratoconus and the treatment options in this episode of A State of Sight.

Welcome to A State of Sight. I’m your host, Isaac Porter, from Porter Ophthalmology and this is your update in ophthalmology and eye care from Raleigh, NC. In our last episode, we gave you the details about corneal hydrops, which is a problem that can occur in patients that have keratoconus that can lead to swelling of the cornea, blurred vision, and pain.

We had a great response to that episode on Youtube and on Twitter from @keratoconusGB and others. We’d like to give more details today about keratoconus, since we didn’t cover very much in the last episode.

You probably remember in keratoconus, the cornea (the clear shield that covers the front of the eye) changes shape from a natural dome shape to progressively bulge forward into more of a cone shape. This can cause blurred and distorted vision that can not always be corrected with glasses or contact lenses.

Keratoconus occurs in about 1 in 2000 people (some estimates are even more frequent), so although it’s not very common, we do see it very frequently here in our office, especially since we specialize in cornea. It is always in both eyes; however, one eye can be significantly worse than the other. Some patients may have a big difference between their eyes, with their good eye or better eye being closer to normal.

Most of the time, the disease starts in the teens and then progresses into the twenties and thirties. The older people get, the less the progression there is and the more keratoconus stabilizes.

There are a few conditions that are associated with keratoconus, like Down syndrome or Marfan syndrome. In some cases, it appears to be inherited or passed down from generation to generation. There are also a few eye problems that are associated with keratoconus, but frequently we see it sporadically, or in a random manner.

We do feel that patients who have eye allergies or rub their eyes frequently are at a higher risk for keratoconus. These patients are particularly at risk for hydrops, like we covered in our last episode.

We are able to diagnose keratoconus by mapping the cornea with corneal topography. This shows the curvature of the cornea and highlights any areas of steepness that may indicate keratoconus. Also, we can use other instruments to measure the curvature of the cornea and the amount of astigmatism present.

Initially, patients with keratoconus may be able to wear glasses, but if this doesn’t completely correct the vision, then they may have to use contact lenses. If people have trouble wearing contact lenses, especially if they can’t see well with contact lenses or they don’t fit well, they may require a corneal transplant in order to restore the clarity of their vision.

This can be done with a traditional full thickness corneal transplant or with an outer layer corneal transplant (DALK, deep anterior lamellar keratoplasty) which preserves the patient's own inner corneal layers and can help decrease their chance of corneal rejection.

There are other new treatments for keratoconus including collagen crosslinking and intracorneal ring segments (Intacs), which can be placed in the cornea. I’ll give you more details of these procedures in future episodes.

Thanks again for joining us on A State of Sight. As always, we hope to interact with you so please post your comments. Until next time, good health and good sight.