Strategies for starting a CXL practice

Corneal crosslinking (CXL) is a minimally invasive procedure that is safe and associated with few complications when the procedure is performed with proper precautions. Because adverse events can still occur, surgeons performing this procedure must also be comfortable managing potential complications, said Clara C. Chan, MD.

Dr. Chan presented pearls for preventing common CXL complications and strategies for managing complications if they arise.

Understanding the problems that can occur is the basis for identifying pre-emptive techniques. They involve preoperative, intraoperative, and postoperative interventions.

To prevent delayed epithelial healing and haze, Dr. Chan said it is important to optimize the ocular surface prior to treatment

“A lot of patients who need CXL have vernal or atopic keratoconjunctivitis and these diseases should be very quiet before performing CXL,” said Dr. Chan, lecturer, department of ophthalmology and vision sciences, University of Toronto, Ontario, Canada. “The ocular surface must also be optimized in patients with severe dry eye, and don’t underestimate the danger rosacea can cause. These patients are notorious for having peripheral ulcerative keratitis and melt, even after simple cataract surgery.”

Preop, intraop strategies

Preoperatively, all eyes receive a typical povidone-iodine scrub with a drop of 5% topical povidone-iodine for infection prophylaxis. To improve comfort, patients are given 0.5 mg lorazepam sublingual 30 minutes before the procedure.

Intraoperative strategies for complication prevention include use of 0.02% mitomycin-C for 30 to 60 seconds to prevent haze in eyes having a combined phototherapeutic keratectomy (PTK) or TCAT PRK.  Ensuring that pachymetry readings remain ≥400 μm reading throughout the procedure is helpful for controlling pain and minimizing more serious risks of uveitis and endothelial decompensation. Hypotonic riboflavin or BSS are used if needed.

Avoiding treatment of the limbus is important for preventing delayed healing, and devices can be purchased to protect this area of the eye

At Dr. Chan’s center, all patients maintain bandage contact lens wear and remain on a topical fluoroquinolone until the epithelium is fully healed. To promote epithelial healing, they are instructed to use preservative free tears as frequently as possible (every hour), and then to continue with the ocular lubricant four times daily after re-epithelialization has occurred.

Topical corticosteroid treatment is used to prevent haze, and Dr. Chan’s regimen begins with dexamethasone until bandage contact lens removal. Then patients are switched to a tapering fluorometholone regimen.

“Darker pigmented patients, however, who are at increased risk for severe haze, are kept on dexamethasone for a more aggressive taper,” she said.

Treatment for pain control treatment includes a topical NSAID for 2 days and oral Percocet for 2 days.
“We found Tylenol #3 does not work well enough,” Dr. Chan said.

Treating complications

Haze is common after CXL, and typically disappears within 6 to 12 months without being visually significant. Persistent haze can occur, however, especially in eyes with advanced keratoconus.

If confluent haze is detected early, Dr. Chan recommended treating for a few weeks with a stronger corticosteroid, such as prednisolone acetate 1% or difluprednate. However, if the haze and decreased vision persists, PTK with mitomycin-C may be considered.

She also presented the use of amniotic membrane, which is prepared by the local eye bank, for managing persistent epithelial defect. The tissue is fixated with a running mattress suture using 9-0 Vicryl.

“We do not use 10-0 Vicryl because it tends to dissolve too quickly before the amniotic membrane is fully dissolved,” Dr. Chan said.

Discussing a case of sterile corneal melt that was reported in the literature, Dr. Chan noted that possible risk factors identified in the affected patient included HLA-B27 positivity.

“Anecdotally, we treated a patient with psoriatic arthritis whose systemic disease was very quiet,” she said. “This individual, however, developed what appeared to be an NSAID corneal melt centrally. Fortunately, healing was achieved with use of intensive lubrication.”

Another complication that has been reported with CXL is sterile infiltrate that typically resolves with topical corticosteroid treatment.

Dr. Chan has no relevant financial interests to disclose.