By Stephen M. Silverman
Updated February 28, 2003 10:30 AM

It’s not an eye infection that’s keeping David Letterman home, after all. It’s shingles — a viral infection that is related to chickenpox, his doctor has revealed.

On Wednesday, Letterman, 55, was forced to turn his “Late Show” desk over to a guest host, in this case Bruce Willis, who’d already been scheduled to appear on the show that night. The night before, Letterman had complained of puffiness in his eye.

“I look like somebody gave me a beating,” he said. “It’s either an irritation, inflammation or infection … For the love of God, does it hurt!”

Turns out that the eye condition was symptomatic of shingles, a viral infection of the nerve roots that typically results in pain and rash. Causes are commonly thought to be physical or emotional stress.

A statement issued by Letterman’s production company, Worldwide Pants, quoted the star’s physician, Dr. Louis Aronne, as saying, “Dave is on his way to a full recovery.”

Letterman’s absence was his first since his recovery from open-heart surgery in early 2000, when he missed several weeks of shows.

For this week, tennis champ John McEnroe and Letterman pal Regis Philbin assumed guest-host duties for Thursday’s and Friday’s shows, respectively, while next week the show will be on an already-planned production break.