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May 28, 2006
Intrastromal corneal ring helps prevent graft rejection, study says
OCULAR SURGERY NEWS EUROPE/ASIA-PACIFIC EDITION June 2006
The implantation of an intrastromal corneal ring in patients undergoing corneal transplant may reduce immune reaction, according to the developer of the device.
“We made and implanted these rings for years to reduce astigmatism, stabilize the wound and improve healing,” said Jörg H. Krumeich, MD, referring to intrastromal corneal rings (ISCR) of his own design, also known as Krumeich rings.
The Krumeich ISCR is made from an alloy of 69% cobalt, 24% steel, 4.5% molybdenum and 2% titanium, according to Dr. Krumeich. It is produced and distributed by HumanOptics. The ring preferably should be used with the guided trephine system or the Hanna trephine, he said.
Barrier to immune reaction
In a study, 179 consecutive cases of penetrating keratoplasty with ISCR implants were compared with 101 eyes that had undergone the same procedure without the ring. The follow-up in all eyes was at least 4 years.
In the eyes where the ring was implanted, the immune rejection rate was significantly lower (two cases out of 179, 1.2%) than in the control group (six cases out of 101, 6%). We also observed that the immune reaction in the eyes with the ring occurred within a few months after the operation, while the immune reaction without the ring had a tendency to occur also much later, up to 2 years postoperatively,” Dr. Krumeich said. He noted that 60% of the rejection cases with the ring could be resolved with the appropriate immunosuppressant therapy whereas only 14% of the rejection cases without the ring could be treated successfully.
New vessel growth
Two consecutive transplants without success, then a third transplant with the ring that works perfectly well and is still clear after 4 years,” Dr. Krumeich said.
In addition, the ring also appears to have inhibitory effects on vascular growth. Once the ISCR is implanted, superficial vessel growth may occur, but it almost invariably stops outside the ring and only in rare cases crosses over.
Posted by aman at May 28, 2006 12:54 AM