Second Sight: Limbal Stem Cells Giving New Hope to Corneal Transplant Patients

For 30 years, Jon Newton has lived with Stevens-Johnson Syndrome (SJS), a rare and serious disorder that causes inflammation of the body's mucous membranes. The impact on his eyes was so severe that he became legally blind, able to count only fingers held up two feet in front of him. About 40 operations on his eyes did nothing to restore his sight. But a remarkable new procedure, in which cells from a healthy eye are harvested and transplanted, paved the way for a successful cornea transplant.

Mr. Newton was 16 when he contracted SJS, an autoimmune disorder triggered by an allergic reaction to certain medications. Two weeks after he took phenobarbital and dilantin, a rash broke out on his arm. His doctor took him off phenobarbital, but the next day blood blisters broke out all over his body, and he had a high fever.

"I was in an intensive care unit for three weeks," says Mr. Newton. "I had a horrific reaction that made its way throughout my body."

The corneas of Mr. Newton's eyes, once clear and healthy, became clouded and scarred. His eyes were excessively dry, and eyelashes were growing into the eyelids. One surgical attempt to restore moisture in his eyes involved transplanting salivary glands to replace defective tear glands; the procedure produced only "two years of pain." Neither electrolysis nor a freezing process to remove the invading eyelashes was successful.

Other operations throughout the years had not helped, and Mr. Newton had little hope that his vision would be restored. That is, until his sister found information on the Internet about limbal stem cell transplantation.

Help from the 'Mother' Cells

Very few people have Stevens-Johnson Syndrome, but anyone who uses chemicals at work or home, is injured by fire, or is a long-term wearer of contact lenses might some day benefit, as Mr. Newton has, from limbal stem cell transplantation. A chemical splash to the unprotected eye can wipe out the eye's outer surface.

According to Prevent Blindness America, 2,000 workers suffer eye injuries on the job every day. Wearing poorly fitting contact lenses over time can also deplete the supply of limbal stem cells. Certain inflammatory diseases can lead to damage and loss of limbal stem cells.

Here's why limbal stem cells are so important. The eye's cornea is the clear tissue that allows light to enter the eye. In addition, it refracts light rays to focus onto the retina. The cornea's outermost section, the epithelial layer, acts as a protective barrier against germs and dust.

Between the cornea and the sclera, the eyeball's white outer coating, is the limbus, where some very important cells reside. Limbal stem cells are "mother cells" that give rise to the corneal epithelial cells. Severe damage to limbal stem cells, whatever the cause, significantly impairs a person's vision, says Dr. David Chu, assistant professor of ophthalmology and director of the ocular immunology and corneal wound healing unit of the division of corneal and external disease at the New Jersey Medical School.

"When the outer eye surface is destroyed and if the limbus is damaged, the corneal surface becomes populated by abnormal epithelial cells," he explains.

"Without the proper corneal epithelial cells, the cornea's surface is no longer smooth, but instead becomes cloudy or scarred. It is unable to properly refract light, significantly impacting the person's ability to see."

Limbal stem cell transplants emerged in the 1970s, but few were done until about five to 10 years ago, says Dr. Chu, who received fellowship training in ocular immunology, cornea, and external disease at the Massachusetts Eye and Ear Infirmary of Harvard Medical School.

The image to the left shows limbal cells being taken from the donor eye.

The limbal stem cells are taken from the healthy eye of the patient, if one exists, or a live donor--usually a sibling or a parent. (The donor eye can function with fewer limbal stem cells.) Less often, limbal stem cells are taken from a cadaver. An emerging approach uses a fraction of the amount of limbal stem cells normally taken from a live donor and grows them in the laboratory.

During this outpatient procedure, which lasts about one hour, some limbal stem cells are taken from the healthy eye or the donor's eye and then transplanted to the affected eye. If the transplant is successful, the limbal stem cells will produce a new layer of epithelial cells in the patient's eye. The success rate of growing the new cells from transplanted limbal stem cells varies from 25 percent to 70 percent, depending on the underlying condition of the eye.

The image to the left shows limbal stem cells being transplanted.

In some cases, a limbal stem cell transplant alone can make a patient's vision considerably better. For other patients, the limbal stem cell transplant sets the stage for what follows -- a cornea transplant.

There are about 40,000 cornea transplants performed each year, which typically are very successful. Multiple eye surgeries and conditions such as keratoconus, where the normally round cornea thins out and becomes cone shaped, and Fuch's Dystrophy, an inherited disease of the eye that causes corneal swelling, can lead to the need for a cornea transplant. Limbal stem cell transplants aren't necessary prior to a cornea transplant where the limbus is intact.

However, says Dr. Chu, cornea transplants will universally fail without the presence of healthy limbal stem cells to give rise to the corneal epithelial layer. For patients with SJS or other immunologically initiated diseases involving the ocular surface, or those whose eyes have been injured by chemicals or fire, the limbal stem cell transplant precedes the cornea transplant.

"We wait about three months after the limbal stem cell transplant before attempting a cornea transplant," says Dr. Chu, who performs both procedures at University Hospital. "If there has been injury or damage to other parts of the eye--the lens, the retina, or the optic nerve, for example--other ophthalmic procedures may be needed to address those problems."

Seeing the Stars

After Mr. Newton's sister read about limbal stem cell transplantation, he decided to give it a try. Because his right eye was damaged beyond repair, the transplant was for his left eye. Another sister was a good genetic match and agreed to be the donor. Dr. Chu, a specialist in treating visual manifestations of Stevens-Johnson Syndrome, was part of the team that performed Mr. Newton's successful limbal stem cell transplant on January 22, 2001. In April, the same doctors performed a cornea transplant on Mr. Newton, who today has 20/30 vision.

Having his sight restored after 20 years of being legally blind is "awesome," says the 46-year-old Mr. Newton. "One of the most awesome sights is to go outside at night and see the stars again. I just look up, and there are the stars."

For more information about limbal stem cell transplant or to make an appointment with Dr. Chu, call The Department of Ophthalmology at (973) 972-2065.


May/June 2002
For 30 years, Jon Newton has lived with Stevens-Johnson Syndrome (SJS), a rare and serious disorder that causes inflammation of the body's mucous membranes. The impact on his eyes was so severe that he became legally blind, able to count only fingers held up two feet in front of him. About 40 operations on his eyes did nothing to restore his sight. But a remarkable new procedure, in which cells from a healthy eye are harvested and transplanted, paved the way for a successful cornea transplant. Mr. Newton was 16 when he contracted SJS, an autoimmune disorder triggered by an allergic reaction to certain medications. Two weeks after he took phenobarbital and dilantin, a rash broke out on his arm. His doctor took him off phenobarbital, but the next day blood blisters broke out all over his body, and he had a high fever. "I was in an intensive care unit for three weeks," says Mr. Newton. "I had a horrific reaction that made its way throughout my body." The corneas of Mr. Newton's eyes, once clear and healthy, became clouded and scarred. His eyes were excessively dry, and eyelashes were growing into the eyelids. One surgical attempt to restore moisture in his eyes involved transplanting salivary glands to replace defective tear glands; the procedure produced only "two years of pain." Neither electrolysis nor a freezing process to remove the invading eyelashes was successful. Other operations throughout the years had not helped, and Mr. Newton had little hope that his vision would be restored. That is, until his sister found information on the Internet about limbal stem cell transplantation. Help from the 'Mother' Cells Very few people have Stevens-Johnson Syndrome, but anyone who uses chemicals at work or home, is injured by fire, or is a long-term wearer of contact lenses might some day benefit, as Mr. Newton has, from limbal stem cell transplantation. A chemical splash to the unprotected eye can wipe out the eye's outer surface. According to Prevent Blindness America, 2,000 workers suffer eye injuries on the job every day. Wearing poorly fitting contact lenses over time can also deplete the supply of limbal stem cells. Certain inflammatory diseases can lead to damage and loss of limbal stem cells. Here's why limbal stem cells are so important. The eye's cornea is the clear tissue that allows light to enter the eye. In addition, it refracts light rays to focus onto the retina. The cornea's outermost section, the epithelial layer, acts as a protective barrier against germs and dust. Between the cornea and the sclera, the eyeball's white outer coating, is the limbus, where some very important cells reside. Limbal stem cells are "mother cells" that give rise to the corneal epithelial cells. Severe damage to limbal stem cells, whatever the cause, significantly impairs a person's vision, says Dr. David Chu, assistant professor of ophthalmology and director of the ocular immunology and corneal wound healing unit of the division of corneal and external disease at the New Jersey Medical School. "When the outer eye surface is destroyed and if the limbus is damaged, the corneal surface becomes populated by abnormal epithelial cells," he explains. "Without the proper corneal epithelial cells, the cornea's surface is no longer smooth, but instead becomes cloudy or scarred. It is unable to properly refract light, significantly impacting the person's ability to see." Limbal stem cell transplants emerged in the 1970s, but few were done until about five to 10 years ago, says Dr. Chu, who received fellowship training in ocular immunology, cornea, and external disease at the Massachusetts Eye and Ear Infirmary of Harvard Medical School. The image to the left shows limbal cells being taken from the donor eye. The limbal stem cells are taken from the healthy eye of the patient, if one exists, or a live donor--usually a sibling or a parent. (The donor eye can function with fewer limbal stem cells.) Less often, limbal stem cells are taken from a cadaver. An emerging approach uses a fraction of the amount of limbal stem cells normally taken from a live donor and grows them in the laboratory. During this outpatient procedure, which lasts about one hour, some limbal stem cells are taken from the healthy eye or the donor's eye and then transplanted to the affected eye. If the transplant is successful, the limbal stem cells will produce a new layer of epithelial cells in the patient's eye. The success rate of growing the new cells from transplanted limbal stem cells varies from 25 percent to 70 percent, depending on the underlying condition of the eye. The image to the left shows limbal stem cells being transplanted. In some cases, a limbal stem cell transplant alone can make a patient's vision considerably better. For other patients, the limbal stem cell transplant sets the stage for what follows -- a cornea transplant. There are about 40,000 cornea transplants performed each year, which typically are very successful. Multiple eye surgeries and conditions such as keratoconus, where the normally round cornea thins out and becomes cone shaped, and Fuch's Dystrophy, an inherited disease of the eye that causes corneal swelling, can lead to the need for a cornea transplant. Limbal stem cell transplants aren't necessary prior to a cornea transplant where the limbus is intact. However, says Dr. Chu, cornea transplants will universally fail without the presence of healthy limbal stem cells to give rise to the corneal epithelial layer. For patients with SJS or other immunologically initiated diseases involving the ocular surface, or those whose eyes have been injured by chemicals or fire, the limbal stem cell transplant precedes the cornea transplant. "We wait about three months after the limbal stem cell transplant before attempting a cornea transplant," says Dr. Chu, who performs both procedures at University Hospital. "If there has been injury or damage to other parts of the eye--the lens, the retina, or the optic nerve, for example--other ophthalmic procedures may be needed to address those problems." Seeing the Stars After Mr. Newton's sister read about limbal stem cell transplantation, he decided to give it a try. Because his right eye was damaged beyond repair, the transplant was for his left eye. Another sister was a good genetic match and agreed to be the donor. Dr. Chu, a specialist in treating visual manifestations of Stevens-Johnson Syndrome, was part of the team that performed Mr. Newton's successful limbal stem cell transplant on January 22, 2001. In April, the same doctors performed a cornea transplant on Mr. Newton, who today has 20/30 vision. Having his sight restored after 20 years of being legally blind is "awesome," says the 46-year-old Mr. Newton. "One of the most awesome sights is to go outside at night and see the stars again. I just look up, and there are the stars." For more information about limbal stem cell transplant or to make an appointment with Dr. Chu, call The Department of Ophthalmology at (973) 972-2065.