Seeking sight: A novel surgey saves one baby's vision

Lane_3400_cropAfter her daughter was born with a non-cancerous tumor obstructing her left eye, Katie Lane spent an afternoon lurching around her Waltham home, her hand blocking one eye, imagining life with monocular vision. With 20/20 eyesight, neither she nor her husband, Dan, even owned reading glasses. Now they were faced with the possibility that their daughter would be partially blind.

Little Kyleigh’s right eye was perfect: pale blue and brimming with mischief. But much of her left eye was covered by a choristoma, a tumor made up of normal tissue that formed in the wrong spot.

After spending five days in the Neonatal Intensive Care Unit (NICU) at Children’s Hospital Boston, Kyleigh was referred to Children’s Department of Ophthalmology. There, she met with Kathryn Colby, MD, PhD, a pediatric corneal specialist from Massachusetts Eye and Ear Infirmary, which recently established a Pediatric Cornea Program at Children’s.

Colby performed a special ultrasound on Kyleigh’s eye that revealed that the tumor extended deep into her cornea, the clear, dome-shaped surface covering the front of the eye. Because the cornea is clear, and, unlike most tissues in the body, holds no blood vessels or veins, many people don’t know it exists. But the cornea plays an indispensable role in sight. Acting as a window to the eye, it controls and focuses the entry of light onto the eye’s lens. The lens then refocuses the light onto the retina, a layer of cells lining the back of the eye that translate light into vision.

The cornea needs to be completely transparent to focus light correctly. But Kyleigh’s tumor was blocking most of it—starving her eye of visual input, and slowly causing it to go blind. “The initial development of vision relies on visual input coming in through the eye,” explains David Hunter, MD, PhD, chief of Ophthalmology at Children’s. Babies are born equipped with all the eye structures needed for vision, but must train their eyes through practice to see. Although it seems like it comes naturally, seeing is actually a learned skill. “After birth, there’s constant remodeling of the brain, as the nerves grow, connect and disconnect,” says Hunter. “When visual input enters the brain through the eye, nerve connections form. As more visual input comes in, these visual pathways grow and are strengthened in their richness and complexity.”

But if the brain doesn’t receive any visual input from an eye, as in Kyleigh’s case, it begins to ignore that eye, and instead forms strong connections to the working eye. If no visual pathways are formed between an eye and the brain, it’s called amblyopia. And while amblyopia is fully treatable when children are young, it becomes irreversible over time.

Time was not on Kyleigh’s side. To develop visual connections in her left eye, she needed a corneal transplant as soon as possible. Although corneal transplant is the most common transplant operation performed in adults in the United States, the traditional operation, using a cornea from a human cadaver, often fails in children.

Children’s immune systems are more vigorous than those of adults, and frequently reject the transplant. White blood cells and blood vessels can invade the new cornea and turn the transparent surface of the eye cloudy. The brain ignores images coming from the cloudy cornea, resulting in amblyopia. Children’s corneas are also less rigid than those of adults, making it difficult—even for the most skilled surgeon—to sew the new cornea perfectly into place and some warping usually occurs. Imagine the surface of the eye like a mirror: If you look at yourself in a normal, flat mirror, you see a perfect, proportional image. But if you look at a funhouse mirror with a warped surface, you see a distorted reflection. Faced with a clear image from one eye, and a misshapen one from the other, the brain chooses the clear picture and ignores visual input from the other eye. “Studies of pediatric corneal transplant patients have shown that even if the cornea is physically clear after two years, because of the variations in shape of the donor cornea, fewer than 50 percent of patients have better than legally blind vision,” says Colby.

The good news was that Kyleigh was a perfect candidate for an artificial cornea, called a Boston Keratoprosthesis, which is a plastic device that’s inserted into a patient’s cornea. Instead of looking through tissue, the patient looks through a piece of plastic, eliminating the risk of immune rejection, clouding and irregular shape. Over 3,000 implantations have been performed since the device was approved for use in 1992, all but a tiny fraction of them in adults. For Katie and Dan, it was Kyleigh’s best chance at sight.

“I was thinking, she’s never going to drive, she’s going to be depending on others forever,” Katie recalls. “I thought she would always have those lesions on her eye, and I was imagining kids at school saying mean things to her.” Although it was a difficult decision—it would be the third time Kyleigh would be put under anesthesia before she was 6 months old—they knew it was their daughter’s only real shot at sight.

During the two-hour surgery, Colby first removed the tumor and then stitched the artificial cornea into place. A permanent plastic contact lens was also placed on her eye. The surgery is only the beginning of a lifetime of care for Kyleigh’s eye—in order to keep it healthy, she must take daily steroid and antibiotic eye drops.lanes_250

Now, two weeks after the surgery, Kyleigh giggles and bounces on Katie’s lap, wielding a plastic pink toy lacrosse stick with both hands. “She was so sore and red after the surgery, it looked like she took on Mike Tyson,” jokes Dan. “But she’s healing really well.” Her left eye doesn’t perfectly match her right—the artificial cornea only comes in one color, a vibrant blue, but if Kyleigh wants, this can be corrected with a colored contact lens. Her parents are already noticing a difference in her activity. “She used to struggle a lot when she was crawling around; she’d go to grab something and miss it by an inch,” says Dan. “Now she’s using her left side more and seems to have more accuracy with her motions.”

Each day, Kyleigh spends some time with a patch over her right eye, to strengthen the surgically repaired left eye and force the development of visual connections. Because she is so young, there is hope she will have good—although not perfect—vision in her left eye. Her parents are holding their breath. “From the minute she was born, she’s been the most curious baby, active and alert, always wanting to get into everything,” says Katie. “I can only imagine how much crazier she’ll be with her vision.”

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