Additive refractive procedures expand keratoconus options, surgeon says

ANAHEIM, Calif. — Additive refractive surgical procedures — those that add material to the cornea instead of removing tissue — can be an option for treating severely progressive keratoconus, according to a speaker here.

“Intralamellar corneal devices and grafts are an exciting new option aimed at restoring corneal thickness and vision in keratoconus patients,” David J. Schanzlin, MD, said at the American Academy of Ophthalmology meeting. Dr. Schanzlin was this year’s recipient of the Barraquer Award, and he delivered the Barraquer Lecture at a symposium on presbyopic correction.

In the United States, 5,000 corneal transplants are performed each year for contact lens-intolerant keratoconus patients, Dr. Schanzlin said. Astigmatism persists in many of these patients, and the rate of keratoconus progression is high (17.9%).

While intralamellar additive procedures have not been proven to stop progression of keratoconus, they can improve vision significantly.

“Intacs (Addition Technology), Ferrara Rings (Mediphacos) and other corneal segments have been shown in multiple studies to correct astigmatism greater than 120°, reduce myopia and produce visual results to 20/30,” Dr. Schanzlin said. Outcomes from the European Keratoconus Study revealed that 22% of patients achieved 20/30 vision and 48% of patients achieved 20/40 vision after Intacs surgery.

“Best-corrected visual acuity results have been exceptional in all PMMA ring studies,” Dr. Schanzlin said. He noted that the location, orientation and size of intrastromal rings did not predict outcome success. Future technology may enable surgeons to customize segments to each patient’s refractive need, he added.

Another promising treatment for keratoconus is intralamellar tissue inserts, Dr. Schanzlin said. In an early clinical study, surgeons have implanted donor buttonholes into keratoconus patients, he said. The corneal graft is then treated with an excimer laser for refractive adjustment.

“Uncorrected visual acuity has been better than postop acuity in these eyes,” Dr. Schanzlin said. In the near future, surgeons may be able to customize these donor implants to suit patients’ corneal dimensions and refractive needs.

While use of additive refractive technology for corneal disease is an off-label application, Dr. Schanzlin said the future implications of this technology will expand the scope of patient care.