What is Keratoconus and How Specialty Contact Lenses Can Help Keratoconus Patients?

Hello I am Dr. Clark Chang from the Keratoconus and Specialty Contact Lens Services inside of our Cornea Department here at Wills Eye Hospital. Often, I get asked questions from patients and my colleagues on how best to manage patients who are diagnosed with Keratoconus, so 

today, I would like to take the opportunity to give a general overview of this eye condition Keratoconus as well as to introduce some of the new medical advancements in Keratoconus treatments, including specialty contact lenses, which are some of the most important medical tools we have in helping Keratoconus patients obtain their best possible vision whether it’s before or after a patient undergoes a surgical eye procedure.

Let’s talk for a moment about the basics of your vision before we get into discussing the condition Keratoconus itself. Like the old adage that compares the workings of our eyes to a camera, our human optics do share some similarities with that of a camera. So in simplified form, think of your retina in the back portion of the eye as your film inside of a camera. The lens system or focusing mechanism in a camera is similar to your cornea (which the front and transparent portion of an eye) plus a magnifier-like lens structure inside of your eye. Together, these 2 elements control the proper projection of the images from the physical world to your retina in the back of eye. Your cornea provides most of the focusing power in this camera analogy, and its natural smooth contour determines how much power it has to provide.   

So how is that related to Keratoconus, you may ask? And that is a great question. Keratoconus is a degenerative and bilateral corneal disorder, which means that this condition can be progressive or unstable through many years of one’s life until its progression slows down and that it affects both eyes although often one eye much worse than the other. Remember I just talked about the smooth contour of the cornea determines its focusing power, when a tissue weakening disease like Keratoconus starts to develop, the corneal tissue is no longer able to hold its original shape and bulges forward in various rate pending individual characteristics and eventually assumes a conical or cone-like shape. The new misshaped corneal contour does not allow the proper projection of images to your retina, which means visual signals of poor quality is being transferred to the visual cortex inside of your brain and leads processing error that can be bothersome and confusing. To put it simply, think of it as going to a 3D movie but you didn’t the 3D glasses to put on you. Patients complain of seeing multiple out-of-focused images that are always blurry no matter how hard or how long they try to stare at an object, which makes it very tiring and difficult to distinguish the location and direction of an object. As well, keratoconus patients also experience bothersome glare and haloes, which makes them uneasy or feel unsafe when driving at night or go out on a sunny day, so many patents discontinues driving and try to avoid going out when its sunny outside. And these are just some examples of the challenges of living with this keratoconus condition.  

Keratoconus was a previously thought to occur in 1 in every 2000 individuals, but has recently been reported to be as high as 1 in every 375 individual by a study in Netherland. Whether it’s because we now have more sensitive clinical tests or just that doctors are more aware of this condition, it certainly appears that we are still learning about this disease and that Keratoconus is not as rare as we used to think.   

Because it is degenerative eye condition, it is important to discuss methods of stabilizing this disease. FDA approved a medical procedure called Corneal Crosslinking in April 2016 for treating patients with progressive keratoconus. It basically uses a photosensitizer eye drop called Riboflavin, which is similar to the composition of vitamin B, and an Ultraviolet light to make the corneal tissue stronger, which stabilizes the condition as well as making your cornea more able to hold its shape. We offer this treatment in Cornea Service at Wills Eye and would be happy to work with you in accessing your risk profile and for the need of this treatment procedure.

In addition to stabilizing Keratoconus condition, corneal crosslinking has also been reported to bring about some improvement to corneal contour. Although doctors are happy to see this result, this is typically not sufficient to achieve the vision improvement needed to function in life for majority of the keratoconus patients. And this is where specialty contact lenses really shines. By being able to control the shape of polymer materials that composes of a specialty contact lens, we are able to the use the customized shape of these lenses to sit on the eye and basically mask the misshapen contour on the cornea. This is likely rebuilding the shape of your cornea without performing a corneal transplant.

Unlike soft disposable lenses that most people think about when I say contact lenses, the shape created on these specialty lenses can be kept throughout the entire day due to the less flexible nature of the material used, thus allowing properly focused image to go on to your retina in the back of the eye and makes it possible to achieve one’s best vision.

Most people think of specialty lenses as just what they used to call “hard lenses” that can be very uncomfortable to wear, but they don’t realize that there has been may advancements made in these specialty lenses. We offer lenses ranging from corneal gas permeable lenses (they are improved versions of what doctors used to call “hard lenses”), soft keratoconus lenses, hybrid lenses and scleral lenses. Each of these lens designs have their own advantages and need to be properly matched to the unique profile in each patient. Once the initial fit is obtained, it also takes series of visits to make further individualized modifications when patients return to clinic – which is similar to being monitored after any surgery. Most patients are unaware of further improvements that can be made to their lenses once they have been given the first lens, and therefore, they often think they have failed specialty lenses and that they are not good specialty lens candidates. This is why we offer our specialty lens services on a slightly different care delivery model where we will work with each patient throughout the series of visits required to make sure that they are getting the most of the prescribed specialty contact lenses that are customized for their condition and their eyes. It may be a timing consuming process but it has a very rewarding end point for both myself and my patients in terms of seeing improvements. Once again I am Dr. Clark Chang from the Keratoconus and Specialty Contact Lens Services inside of our Cornea Department here at Wills Eye Hospital.