For a while, people with a serious eye condition called keratoconus can get by with prescription glasses or contact lenses, although they must ramp up regularly to stronger and stronger lenses.
But in many cases, keratoconus (ker-uh-toh-koh-nuh-s), a weakness in the structure of the cornea causing it to thin and bulge into a shape more like a cone than a dome, eventually requires a corneal transplant.
Now, doctors at UCI Health Gavin Herbert Eye Institute (GHEI) offer crosslinking, a non-surgical keratoconus treatment shown in European studies to be 90 percent to 95 percent effective.
Crosslinking, approved in 2016 by the U.S. Food and Drug Administration, often arrests the progression of keratoconus so that patients can avoid a corneal transplant altogether, says GHEI Medical Director Dr. Sumit (Sam) Garg.
‘Like looking through an unfocused microscope’
GHEI patient Andrew Ochoa, 25, began to experience symptoms just before starting college. First he tried glasses, but soon had to move to hard contact lenses. “It’s like you’re looking through an unfocused microscope,” Ochoa says.
“I like to read and if the illness gets bad enough, you can’t read, you can’t write,” he adds.
“Keratoconus can lead to significant problems, and it’s not like you can just put on thick glasses. Your eye is deforming in front of you, and you can’t do anything about it.”
The cornea contains interwoven layers of collagen that give it structure. “These bridges are thought to be weaker in people with keratoconus,” Garg says.
Strengthening the cornea
The crosslinking procedure involves temporarily removing the epithelium, the protective covering of the cornea, then saturating the cornea with riboflavin and exposing it to ultraviolet A (UVA) light.
The precise mechanism isn’t fully understood, but the procedure increases the number of “crosslinks” that give the cornea its structure, says Garg, an associate clinical professor in the UCI School of Medicine’s Department of Ophthalmology.
“Think of it as the struts on a bridge,” he says.
“If you increase the number of struts, you strengthen the bridge. But in the case of crosslinking, those struts are biochemical.”
Crosslinking also is effective in patients with corneal ectasia, a bulging or instability of the cornea that is an occasional complication of some LASIK surgery. Garg says that condition generally occurs in patients who weren’t great candidates for LASIK procedure surgery to begin with.
Family history is a factor
Overall, keratoconus occurs in about one in 2,000 people, but it is more common in people with a family history of the condition as well as those with certain associated medical conditions.
Patients with the condition are also more likely to rub their eyes continually, although the relationship between the rubbing and the weakened cornea isn’t fully understood.
Keratoconus usually emerges when people enter their late teens or early 20s, with symptoms that include nearsightedness and astigmatism. Both eyes are affected, and one is usually worse than the other.
It is a progressive condition. “Patients have to get glasses and contacts, but those keep changing and changing as they get more nearsighted,” Garg says.
Condition stabilizes with age
As the patient matures, and with exposure to sun, the cornea hardens and its structure becomes more stable, he said.
The key with crosslinking is to catch keratoconus early and treat it so that the shape of the cornea is normal enough to require only glasses or contacts by the time the cornea matures.
Ochoa underwent the crosslinking procedure on both eyes in May and June of 2017, shortly after he graduated from UCI with a degree in literature. He began noticing improvements in his vision almost immediately.
“I’m really glad I did it because now I don’t have to worry about it — forever,” Ochoa says.