Keratoconus and Scleral Contact Lenses

Keratoconus is a condition of the cornea (the clear front part of the eye) that can cause major vision problems in patients. Keratoconus most often affects patients when they are younger (20’s through 40’s) and is caused by a thinning and sloping of the cornea. Normally, the cornea should be perfectly round, kind of like a ping pong ball that was cut in half. Instead, the cornea droops down and becomes much steeper towards the lower portion. This makes the shape much more irregular and light rays scatter instead of being focus on the back of the eye.

Here’s a very basic diagram:

Note how in the top picture, the light (the blue line) passes straight through the cornea and focuses on the back of the eye. This is how someone who is wearing their optimal glasses or contact lens prescription has light focused on their eye. 

The second image is a cornea with keratoconus. Instead of being evenly round, the cornea is drooping down lower. Now light hits the cornea in an irregular pattern and causes the light rays to scattered and focus in the wrong areas!

Unfortunately, many patients with keratoconus (or other corneal ectasias) are not able to have a glasses prescription that can focus all those light rays into the correct spot on the back of the eye like in the top picture. Instead, many of these patients need to have a scleral contact lens fit.

So how does a scleral lens help irregular corneas?

A scleral contact lens is a large rigid contact lens that is custom fit to a patient’s eye. They are one of the most customizable contact lenses that can be made, as we can control for about 12+ different parameters. For most custom soft lenses, we can only control for about 6 parameters on any given lens!

These lenses are beneficial in conditions like Keratoconus, Pellucid Marginal Degeneration, Corneal Ectasia, post-Refractive Keratotomy, Corneal Scarring, Dry Eye, and many other conditions. While wearing a scleral lens, saline provides a cushion between the eye and the lens to help correct for the many irregularities that can affect someone’s vision. 

Even more exciting, we can now create lenses that account for higher order aberrations! These lenses are designed for patients who experience ghosting, star bursts, halos, and other visual issues in their glasses or contact lenses to try to further reduce issues that many patients face. 

Dr. Nick specializes in fitting scleral contact lenses and enjoys it greatly; helping restore vision in patients who have corneal damage or disease is one of his favorite parts of practicing!

Wavefront Designed Sclerals

Many patients who need scleral lenses suffer from what are known as “higher order aberrations.” These are difficult to correct visual phenomenon such as ghosting, starbursts, and haloes around lights. In some cases, these can be so severe that someone might not be able to improve their vision beyond a certain level. Until recently, many patients had to just live with the ghosting in their vision. 

As technology has continued to improve, we now have the ability to fit wavefront guided scleral lenses. These are lenses that take high order aberration correction into account when they are made using a special camera called an aberrometer. 

While we can’t guarantee they will eliminate all the aberrations patients experience, we have seen great success in reducing them to more manageable levels!