Metal corneal ring may reduce immune rejection after PK

LISBON, Portugal — A type of intrastromal corneal ring may be responsible for lower immune rejection rates in corneal graft patients, according to one surgeon.

Jorg H. Krumeich, MD, presented 2-year results with the ring here at the European Society of Cataract and Refractive Surgeons meeting. In his study, 268 patients had the 8-mm cobalt-titanium-molybdenum alloy ring (HumanOptics) sutured into their penetrating keratoplasty wounds. Postoperative results were compared with 285 patients who did not have the ring inserted after surgery.

Keratoconus was seen in a similar number of patients in both groups, he said. About 10% of the patients who had the rings implanted presented with keratoconus, compared with 17.6% of those in the control group without the ring.

Postoperative best corrected visual acuity was similar between the groups, he said. After 5 years, the eyes with the ring may be more stable than those without a ring, but the difference was not statistically significant, he said.

“So why should we continue to use the ring if there does not seem to be any inherent advantages?” he asked.

The rings may have been responsible for a reduction of immune rejection by about 25% in the ring group compared with the control group, he said.

“The ring seems to offer three outright advantages: protection against deformation, inhibition of ingrowing vessels and postop astigmatic control,” he said.

He added there are secondary measures as well, and that “wound healing seems to be faster” when the ring is present.