A Harvard professor at the Medical School (HMS) said yesterday that he has invented a new contact lens which enables people with severe corneal damage to see clearly.

Dr. Perry Rosenthal, assistant clinical professor of ophthalmology at HMS and an eye surgeon, says his lens has worked in about 80 percent of test cases.

The U.S. Food and Drug Administration recently approved the invention, called the Boston Scleral Lens, making it legal for distribution to eye doctors around the country.

The lens is made from a new plastic called Equalens II, which allows oxygen to diffuse freely across the lens into the eye. The cornea needs oxygen for the eye to function properly.

The cornea is the transparent membrane that covers the iris--the colored part of the eye--and the pupil. Occasionally, it becomes scraped, cut or dried out, which may lead to partial or complete loss of vision andoften causes pain.

The new lens, which costs $2,500, rests on thesclera--the white part of the eye--and arches overthe cornea, creating a tiny gap.

Patients fill the lens--which is about the sizeof a quarter--with a lubricant, which in turnfills the space between the lens and the eye,providing lubrication to the irritated cornea andallowing the patient to see normally.

The new plastic was developed by the PolymerTechnology Corp. in Wilmington, Mass., whichworked together with Rosenthal's team indeveloping the lens.

Rosenthal founded Polymer Technology, and latersold it to Bausch & Lomb, Inc. He has been doingresearch on the lens since the 1970s

Kathleen Melvin, a secretary, said the BostonScleral Lens has changed her life.

Melvin said she is afflicted with a raredisease that prevents her eyes from producingtears, causing severe corneal damage.

"I tried all kings of wacky treatments. Nothingworked," Melvin said. "But I tried the BostonScleral and I felt like I had gotten my lifeback."

"I do a lot of typing and computer work, andnow I am able to do it without pain," she added.

Bernard Malone, another patient of Dr.Rosenthal who has tried the lens said it isextremely effective.

"I've had four corneal transplants, and untilnow, I had no chance of ever seeing properly,"Malone said.

"Now I can drive--even at night," he said."It's made me a productive, normal person again."

Rosenthal said he is very enthusiastic aboutthe lens. "It's wonderful to see the lives ofthese people reshaped and for them to becomeproducing members of society again," he said.

Developers of the lens say the hefty price willnot translate into profits for the doctors.

Rosenthal said he is in the process of settingup a non-profit organization called the BostonScleral Lens Foundation for Vision Rehabilitationto educate people about the lens.

Cynthia Sheppard, a marketing manager atPolymer Technology, said the bulk of the moneyearned from sales will go directly to theFoundation.

"The Foundation will use the money to traindoctors around the world to fit patients with thelens," Sheppard said. "In addition, informationwill be shared on different techniques for lensfitting and other procedures involving the lens.