New Surgical Technique Will Give Baby Jacob Prosthetic Eyes

Toddler Jacob Johnson of Grand Rapids, born with a rare condition called anophthalmia, has no eyes. He suffers from a total absence of ocular soft tissue and has no optic nerves. His eye sockets are also smaller than in a normal infant.

Christine C. Nelson

While Jacob's blindness cannot be overcome, it will be possible to provide him with a normal appearance thanks to a new surgical technique developed by Christine C. Nelson, an ophthalmic plastic surgeon and associate professor in the Department of Ophthalmology and Visual Sciences in the U-M Medical School. Nelson’s surgery will make it possible for Jacob to eventually be fitted with prosthetic eyes. Jacob was referred to Nelson by his Grand Rapids ophthalmologist, Patrick Droste, M.D.

In order to prepare his eye sockets for the eventual prostheses, Nelson transplanted amniotic membrane within the bony structure of Jacob's two orbits. She then placed two conformers, synthetic "shells," inside the orbit that will help his sockets to open and expand.

Parents of children who are born with bilateral anophthalmia must deal with the realization that their children will be blind and disfigured. "Dealing with anophthalmia is like a roller coaster," says Jacob's mother, Michelle. "Sometimes it just hits you like a ton of bricks. But as time passes and we see how happy Jacob is, the pain lessens." While blindness cannot be helped, disfigurement can be essentially eliminated by the use of carefully created prosthetic eyes that are produced by an ocularist, a person who combines artistry and engineering. The ocularist works closely with the ophthalmologist and the patient to create life-like artificial eyes that fit and move comfortably within the sockets. They are made of polymethylmethacrylate, the same material that is used to make hard contact lenses.

In order to prepare for a cosmetically pleasing prosthesis, it is critical to stimulate the socket early so that it can become large enough to accommodate a series of artificial eyes as the baby grows through childhood. The psychological benefits of having prosthetic eyes that are reasonably sized for a child's growing face and that are painstakingly painted to mimic an organic eye are enormous.

The challenge is to find a way to stimulate the bone so that it grows and retains its shape as it expands. In microphthalmia, where the sockets are small but there is some remnant of soft tissue or a cyst that stimulates the socket, conformers alone often suffice. In anophthalmia, however, nothing has caused the socket to expand. In fact, the orbital bones grow much thicker, causing an even greater impedance to attempts to enlarge the sockets. In such cases, there is a limited amount of conjunctival tissue in the socket. The conventional treatment is to make an incision in the conjunctiva to allow for an expanded socket. The resulting gap, however, has to be bridged with biologically compatible tissue so that the net amount of conjunctiva can be increased. Until recently, this bridge was mucosal tissue taken from the inside of the patient's lip or cheek. While effective, this procedure created two wounds on the patient that required healing: the socket and the mouth. Further complicating an already difficult situation is the fact that infants do not have much mucosal tissue to harvest, making it sometimes necessary to do the surgery in stages.

Within the past year, a different procedure has been developed that avoids having to take tissue from a patient's mouth — amniotic membrane transplantation. It was first introduced into the medical literature in the 1940s, but because it was difficult to store and transplant the tissue, it was not very successful until recently.

Amniotic membranes are donated by women who have undergone deliveries by Cesarean section. There are many advantages to using amniotic tissue rather than autologous tissue. Amniotic membrane forms the innermost layer of the fetal membrane. Because fetal membrane has antimicrobial properties, these transplanted membranes have fewer risks of developing postoperative infections. In addition, because there are no "live" cells, there is no risk of rejection or the graft-versus-host-disease that so commonly sabotages allograft transplants. There are, also, large pieces of this tissue available for use. Finally, some physicians believe that amniotic membrane transplants have a cosmetic result that is superior to an autologous graft. "What's even better," says Nelson, "is that the wound seems not to hurt quite as much as when mucosal tissue was used. Any doctor who deals with kids knows that the number one priority is to minimize their pain if it's at all possible."

Nelson can be reached at cnelson@ umich.edu.