BANGOR – Earlier this spring, over the course of a week or so, Anne Reed realized her eyesight was failing. There was no pain involved, only a rapid loss of visual clarity and focus.

Early Thursday afternoon, the 84-year-old Bar Harbor resident was at Eastern Maine Eye Associates in Bangor, waiting to be taken into the operating room for a corneal transplant. She seemed calm and composed – “hopeful,” she said, that the outpatient procedure would restore the damaged vision in her left eye.

The cornea is a clear, dome-shaped structure – about as thick as a penny, but flexible – that covers the front surface of the eye. Its clarity is an essential component of healthy vision, responsible for about 60 percent of the eye’s ability to focus.

In some individuals, said Reed’s surgeon, Dr. Garth Wilbanks, the cornea becomes clouded, often because the bottom tier of specialized cells, known as Descemet’s membrane, loses the ability to extract excess fluid from the cornea.

“Then it fills with water and becomes cloudy,” Wilbanks said. That’s what happened to Reed, possibly as a result of an earlier eye surgery.

Scarring, disease, infection or trauma can also lead to a loss of corneal clarity. In the majority of cases, lost vision can be restored by replacing all or part of the cornea.

A high rate of success

Each year in the United States, about 33,000 people receive a new cornea donated from another person who has recently died. More than 90 percent of cornea transplants performed in this country are successful in restoring the recipient’s vision, according to a recent study funded by the National Institutes of Health.

Until now, many eye banks have limited donor eligibility to age 65 and under because of uncertainty whether tissue from older donors performs as well as that from younger donors.

The recent five-year study, completed in December 2007, is the first scientific survey of how well corneal tissue from older donors performs. Eastern Maine Eye Associates is one of 80 sites in the United States that participated in the national study, which determined that corneal transplants using tissue from older donors are just as likely to last five years or longer as transplants using tissue from younger donors.

The study has prompted a recommendation that all eye banks expand their guidelines to include donors up to age 75.

For a decade or more, the availability of donated corneas in this country has been adequate, in part because eyes are among the most frequently donated organs.

But with an increase in demand for corneal transplants as the general population ages and surgical techniques improve, and with new federal restrictions tightening some donor eligibility guidelines, medical providers such as Wilbanks have feared that a shortage could be looming.

“A shortage is not a long ways off,” he said. “This study will help avert it.”

Locating a cornea

Reed waited a month for her transplant, but that was only because the surgical schedule at Eastern Maine Eye Associates was crowded. Generally, Wilbanks said, a cornea can be located within a week. In an emergency, overnight procurement is often possible.

Organ donors are anonymous, but basic information comes with each cornea. The man who donated his cornea to Reed was 52 years old, white and from the mid-Atlantic region. He collapsed last Friday, May 9, after an asthma attack and spent several days on life support before being declared brain-dead at 4:10 p.m. Monday. “Subject was a multi-organ and tissue donor,” according to the information that came with the donated cornea.

Covered from head to toe in a burqalike blue paper surgical drape, with only her left eye exposed, Reed remained awake and responsive throughout Thursday’s transplant procedure, though a local anesthetic kept her from experiencing any discomfort. A lid retractor held her eye wide open.

Wilbanks worked with steady hands, delicate instruments and a powerful microscope, first removing a disc-shaped piece of the damaged inner layer of her cornea through an almost invisible incision, and then custom-fitting a piece of the donor tissue to replace it. He inserted the circle of new tissue, no bigger than the tip of a drinking straw, and unfolded it like a tiny, transparent pie crust over the gray hole of Reed’s pupil and the lens behind it.

The whole process took a little more than an hour. Reed said she planned to stay the night at an area hotel and see Wilbanks again this morning before returning to Bar Harbor this afternoon.

More information about the corneal transplant study is available online from the National Institutes of Health at www.nih.gov/news/health/apr2008/nei-01.htm.

mhaskell@bangordailynews.net

990-8291