My hopes of living a life without glasses or contact lenses were dashed last month.
It happened at a consultation for LASIK surgery. To qualify for the corrective laser procedure, I had to go through a series of eye exams that checked pupil size, tear production, visual acuity, and cornea thickness. That last one is what sealed my fate. “Yours are dangerously thin,” the technician said. It’s a disease called keratoconus, which probably started when I was around 18 years old, the doctor explained. I sat there confused: This was news to me. “What do I do?” I asked.
“Get an eye exam every year to see if progresses,” the doctor said. “Otherwise, just keep wearing your corrective lenses, and you should be OK. But don’t ever get LASIK – it’s too risky.”
I walked out of his office disappointed, eyes still dilated from all the drops, but thankful. Even though it’s unlikely my disease will progress at this point in my life – thinning typically begins in the teen years and stops as people age and wear lenses – it’s better to be in the know, so I can educate myself about any treatments I may need if it does.
Turns out, I already knew about one of them, I later realized. Four years ago, I wrote about a treatment called crosslinking that ophthalmologists at Penn’s Scheie Eye Institute and other hospitals had been studying for years and continue to do so through today.
It was poised to be game changer. Keratoconus, which occurs in about 1 in 2,000 Americans, is a degenerative disease in which the cornea thins and bulges into a cone-like shape. Some lose their vision over time, managing it with corrective lenses, while others who are worse off need a corneal transplant. But that’s where treatments stopped. Corneal collagen crosslinking, or CXL, works to strengthen the cornea’s chemical bonds with a riboflavin dye and ultraviolet light. Thirty minutes of dye followed by 30 minutes of UV light proved to be safe and slow disease progression in clinical trials. Two years later, in 2016, the U.S. Food and Drug Administration approved it.
“There was nothing available to treat keratoconus or to prevent its progression,” said Stephen E. Orlin, MD, a cornea specialist and refractive surgeon at Scheie, “so it was a huge breakthrough.”
Now patients with progressive keratoconus can receive the treatment at Scheie and other centers around the country. Orlin has performed crosslinking over 25 times, including the clinical trial procedures.
It’s a relatively simple, minimally invasive procedure to perform – “one-and-done type of treatment,” Orlin said – but it’s targeting very intricate mechanics in the eye. The corneas are made up of millions of tiny little bundles of collagen fibers bonded together that run from one side of the cornea to the other.
“Imagine a 12-foot step ladder that only had three rungs – it would be very unstable,” Orlin said. “If you had 30 rungs, it would be much more secure. The bonds that link across the cornea are like the rungs of a ladder. If you can generate more of those bonds between the fibers, you can make the collagen stiffer, so that it doesn’t bulge out and thin.”
Stephen E. Orlin, MD
But before the patient receives the dye to begin that strengthening process – two drops every two minutes for 30 minutes – the surgeon must first scrape off the epithelial layer, so the dye made up of vitamin B2) can seep into the cornea. The corneal abrasion can cause pain in the immediate post-procedure healing phase, and carries a small risk of scarring and infection.
Because of the pain and risks, researchers have been working to see if they can avoid the step of removing the epithelium. The FDA-approved treatment is for what surgeons call “epi-off,” short for epithelium, while the new approach being studied is called “epi-on.”
“There is some controversy between the two procedures,” Orlin said. “If you can do the ‘epi- on’ with crosslinking, ideally that would be a better operation. But the controversy is whether or not it is as effective as ‘epi-off’ crosslinking. The reason it may not be is because the riboflavin dye has to be absorbed into the cornea, and the dye doesn’t penetrate the epithelium very well.”
Orlin has his doubts about the approach, but ongoing studies, he said, will help answer whether it can get the job done just as well.
Keratoconus is generally spotted during a routine eye exam in younger people or because people complain of blurred vision. (Or, like me, when being examined for LASIK or other eye surgeries). If it is caught too late, and a patient’s vision is seriously compromised, a corneal transplant may be needed. In that surgical procedure, the cornea is replaced by donated corneal tissue in its entirety or in part.
This drastic step has become less common in the United States for keratoconus patients, according to a Penn paper co-authored by Orlin and published in the journal Cornea last year, in part because of the advancement of contact lens technology. Internationally speaking, crosslinking, which gained approval in other countries long before the United States, has likely helped bring down worldwide transplantation numbers, a trend that Orlin believes is now being mimicked in the United States.
Still, transplant techniques continue to move forward. Before, when a patient had a corneal disease, no matter what layer of the cornea was involved, they received a full thickness, new cornea. These days, for keratoconus, eye surgeons can transplant only the layers that are damaged using newer techniques for a procedure known as deep anterior lamellar keratoplasty, or DALK. It’s significant because the patient’s own endothelium is left intact, which significantly decreases the risk of transplant rejection.
“That’s a huge advance,” Orlin said. “The cornea will stay good for life.”
Digging deeper into keratoconus opened my eyes even wider, and only reinforced what the LASIK doctor said that day. A disease, after all, can take on a new meaning when it’s affecting you. Keep wearing glasses and get an exam every year to stay on top of it – and healthy. That’s all I’m hoping for now.