September 2017

COVER FEATURE

Update on Crosslinking
Behavioral impacts on crosslinking


by Rich Daly EyeWorld Contributing Writer



Patient behaviors to watch for when providing crosslinking treatments

Some patient behaviors can affect the success of crosslinking to strengthen the cornea and halt progressive keratoconus.
Young keratoconus patients seen by Edward Holland, MD, professor of ophthalmology, University of Cincinnati, fall into two groups: those with severe allergic eye disease and those for whom rubbing is habitual.
Among allergy sufferers, the eye rubbing is secondary to their underlying problem.
“Before we perform any procedure such as crosslinking or keratoplasty, we want to aggressively manage their allergic eye disease,” Dr. Holland said.
Among other patients with no clinical findings of allergic eye disease and no history of any atopic findings, such as asthma or eczema, sometimes the family will say that the patient has been a chronic eye rubber and it is just a habit.
“Maybe that patient was an allergy patient at a younger age and learned how to eye rub and it has become habitual,” Dr. Holland said. “Invariably patients say they don’t rub their eyes, then we ask the family members and they say the patient rubs their eyes all day long.”
Alan Carlson, MD, professor, Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, also screens all such patients for eye rubbing and the possibility that they could be applying pressure to their eyes during sleep.
“Fortunately, the word is getting out with regard to the role of eye rubbing accelerating progression of ectasia,” Dr. Carlson said. “I want to make sure that the crosslinking procedure is not simply making the cornea more resistant to ongoing eye rubbing.”
Patients can help break the eye rubbing cycle by wearing a shield at night and using additional lubrication during the day to lubricate the surface and reduce lid wiper epitheliopathy, Dr. Carlson noted.
Dr. Holland recruits the family members to get an accurate assessment of whether the patient has stopped the eye rubbing or not. He hasn’t seen a case where a chronic eye rubber caused a recurrence of ectasia post-crosslinking, but theoretically they could.
“I managed a teenage girl with early and progressing keratoconus. She was a confirmed eye rubber by family members. We convinced her to stop rubbing her eyes, and over the next 12 months her keratoconus regressed and her topography normalized,” Dr. Holland said.
Dr. Carlson also addresses blepharitis, dry eye, and the ocular surface to make sure that postop healing will tolerate a bandage contact lens for several days and progress without complications.

Sleep position

Another group of patients who can have not only ectasia but other types of nocturnal trauma are those patients who sleep face down. They are often sleep apnea patients, Dr. Holland noted.
“They can induce floppy eyelid syndrome, chronic conjunctivitis, and this trauma can induce changes in the cornea leading to ectasia,” Dr. Holland said. “We’re starting to see the diagnosis of sleep apnea in younger patients, especially in younger obese patients. It’s not common but should be in the differential diagnosis of a young keratoconus patient.”
Dr. Carlson has observed and reported the apparent subset of patients with keratoconus who have findings outside of the cornea, showing a propensity for weight gain, obstructive sleep apnea, floppy eyelid, and mitral valve prolapse.
“It’s suggesting that keratoconus patients may not only have a floppy cornea but also a floppy belly, floppy soft palate, floppy eyelid, and a floppy mitral valve,” Dr. Carlson said. “I think it is worth screening for this by a review of systems.”

Contact lenses

Dr. Holland noted that contact lenses can be associated with ectasia, with patients who have a long-term history of rigid contact lens wear especially wearing relatively flat lenses over the years.
“If someone was crosslinked and went back to the contacts, that could be a potential issue,” Dr.
Holland said. “I have seen it in patients with a history of long-term rigid lens wear who come in with a later onset of keratoconus. Typically, that cone is different than the ones we see in a young adolescent—it’s more of a central cone, less scarring, less severe steepening. There’s certainly evidence that long-term contact lens use can induce ectasia.”
Dr. Holland performs serial topography every 6 months post-crosslinking for the first couple of years to make sure there is no change in astigmatism and steepening. In such cases, he would perform a second crosslinking procedure if the patient shows evidence of recurrent ectasia.

Further issues

Among dietary considerations, Dr. Carlson noted the cornea has the highest concentration of vitamin C, and he has been recommending 500 mg of vitamin C daily for any patients undergoing corneal surgery.
The only other issue surrounding crosslinking patients that Dr. Carlson noted is that it is important to not let them become “corneal cripples.”
“What I mean by that is that it is common for these patients to have never heard of the disease prior to their diagnosis,” Dr. Carlson said. “Then they are told it is genetic, yet only 7% of keratoconus patients have a family member with the same diagnosis. They can feel alone, isolated, and even defined by their disease. It can impact their world view, their job, sports, hobbies, and social interactions. It is extremely important to emphasize that we have major advances surgically and non-surgically that can benefit their condition and quality of life.”

Editors’ note: Dr. Carlson has financial interests with TearScience (Morrisville, North Carolina). Dr. Holland has no financial interests related to his comments.

Contact information

Carlson
: alan.carlson@duke.edu
Holland: Eholland@holprovision.com

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