WEDNESDAY, July 1 (HealthDay News) -- Among patients with herpes simplex virus who need a corneal transplant, testing for inflammation biomarkers before the surgery could improve outcomes, U.S. researchers say.

The cornea, which covers the front of the eye and helps focus light for vision, can be damaged when herpes simplex virus infects the eye. In some cases, the damage is so great that the cornea needs to be replaced with a transplant, according to background information provided in a news release from the American Academy of Ophthalmology. It was already known that cornea transplants were more likely to fail in patients with herpes simplex virus infection than in those with other eye conditions. This is true even when the virus doesn't appear to be active in patients.

Researchers at the Kellogg Eye Center at the University of Michigan suspected that patients with herpes simplex virus infection might have corneal inflammation that increased the risk of corneal transplant rejection, but couldn't be detected during pre-ransplant clinical examinations.

To test their theory, the researchers analyzed corneal tissue removed from 62 patients. Even though herpes simplex virus had been inactive for six months before surgery in 81 percent of the patients, the researchers found microscopic evidence of inflammation in 74 percent. They also noted that the rate of transplant failure correlated with the presence of this biomarker.

"It is also possible that treating inflammation intensively before corneal transplant surgery would reduce the risk of rejection," study lead author Dr. Roni M. Shtein, a cornea specialist, said in the news release.

The study appears in the July issue of the journal Ophthalmology.

More information

The Eye Bank Association of America has more about corneal transplant.