COMMENTARY

Corneal Crosslinking: Advancing the Treatment of Keratoconus

Christopher J. Rapuano, MD; Brad H. Feldman, MD

Disclosures

May 17, 2016

Editorial Collaboration

Medscape &

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Christopher J. Rapuano, MD: Hello. I'm Dr Christopher Rapuano, chief of the Cornea Service at Wills Eye Hospital. I'm here with my colleague, Dr Brad Feldman, who is also on the Cornea Service.

This is a collaboration between Wills Eye Hospital and Medscape Ophthalmology.

We're here to talk about a new development in the treatment of keratoconus. Brad, all eye care providers see patients with keratoconus. What comes to mind when you think about keratoconus?

Brad H. Feldman, MD: Keratoconus is a condition that we usually see developing in young adults, teenagers, and even in childhood at times. Typically these patients present with decreasing vision, increasing nearsightedness, and astigmatism. They'll come in complaining that they're just not seeing as well as they'd like to. Sometimes they also have poor night vision. These vision changes are sometimes not correctable with glasses. Some patients will go on to get glasses, and soon after they find that they are still just not seeing that well. Sometimes it can take a while before we make the diagnosis.

Dr Rapuano: I agree. A lot of times people say that they got glasses 6 months ago and the glasses don't work. Are there any kind of predisposing risk factors you ask patients about?

Dr Feldman: Family history is a small factor. About 6% of patients with keratoconus will have a first-degree relative with keratoconus.[1,2] You often find that these patients will be rubbing their eyes in your chair. So we'll ask about eye rubbing, allergies, eczema, atopy, and asthma. However, these patients are often aggressive eye-rubbers, not just the mild rubbing that you'll see. They'll rub right into their eye with their knuckles. It's often not subtle.

Dr Rapuano: The rubbing is often impressive. Having said that, sometimes you ask the patient if they rub their eyes and they say, "Absolutely not." Then you ask their spouse or family member and they say, "Yes, they do!" It's amazing that some patients don't realize how much they rub their eyes.

Dr Feldman: That's right. It could be a subconscious habit for them.

Dr Rapuano: What are the standard treatments for keratoconus?

Dr Feldman: Until recently, keratoconus has been a disease that we just tried to manage by asking people not to rub their eyes. We think that may cause some trauma that could progress the disease. Then we try to give them the best vision possible, despite the fact that the disease may continue to get worse. This includes fitting them with glasses with astigmatism correction and contact lenses. Specifically, there are some special contact lenses that can correct high levels of astigmatism. Beyond that, we really only have had treatment for advanced disease. The main treatment for people with advanced disease was corneal transplantation, which is curative for a lot of patients but inherently has a lot of risk. We had a few other things that we could try, like corneal inlays (eg, Intacs®), which were often used to help improve the contact lens fit. There hasn't been anything great to stop the disease at the early or moderate stage.

A Huge Breakthrough

Dr Rapuano: Recently, the US Food and Drug Administration (FDA) approved corneal crosslinking for the treatment of keratoconus. What's the story with that?

Dr Feldman: This is a huge breakthrough for our patients. Corneal crosslinking is a treatment that can effectively halt the progression of the disease for patients. What it does is strengthen the cornea. Keratoconus is a disease where the cornea is weak and more elastic than it should be. It takes on a conical shape instead of being nice and spherical, dome-like, and round. A number of years ago at the Technical University of Dresden, German investigators showed experimentally that by treating the eye with ultraviolet (UV) light after it's been soaked with riboflavin, they could cause a reaction that strengthened the cornea through crosslinking.[3] Over time, clinical studies in humans have shown, without a doubt, that this is an effective treatment.[4,5,6,7] What is now available is that we can crosslink our patients by giving them riboflavin drops and exposing them to a certain UV device to strengthen their cornea and prevent the disease from progressing.

Dr Rapuano: Interestingly, this has been available around the world for 5 or 10 years in some countries. We're very excited that it's now going to be available in the United States. In the registration trials used for FDA approval,[8,9,10,11] what age were the patients and what diagnoses were being treated?

Dr Feldman: In the registration trials, patients were included from ages 14 years and up. Most of the patients were in early adulthood. What was being treated was progressive keratoconus. Keratoconus is a disease with a wide spectrum of severity and it doesn't always progress. Some people may have the disease and the diagnosis may be made, but they may not get worse. These are only patients who were getting worse; their glasses prescription was getting stronger and the shape of their cornea was getting worse. Those were the patients who were being treated.

Dr Rapuano: In my practice, we were involved in Avedro's registration trials for several years and we found good results in the small number of patients that we treated. We're very happy to have this FDA-approved and available soon. Do you have any idea when it will actually be available for patients in the United States?

Dr Feldman: Avedro (the company that received the FDA approval for their device) has said that within the next several months or toward the end of the year, they should be making the product available.

Dr Rapuano: They need to upgrade their machine and get them out to the trial investigators first and then to the rest of the doctors who want to use it. I know we're very excited in my practice to be able to offer this to patients, and I'm sure you are too.

Dr Feldman: I'm very excited to offer this. We've been basically telling these patients, "Okay, we'll help you along the way, and when things get bad we can do a transplant." It will be great to offer them something much better and earlier on.

Dr Rapuano: I'm Chris Rapuano, with Brad Feldman from the Cornea Service at Wills Eye Hospital, coming to you from the Wills Eye Alumni Society newsroom at Wills Eye in Philadelphia. This has been a collaboration between Medscape Ophthalmology and Wills Eye Hospital. Thank you very much.

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