When Bobby Mack walks down the hallway at Thomas S. Wootton High School in Rockville, he smiles and says hello to the friends he passes. But when someone offers him a high five, the 17-year-old doesn’t always return the gesture.
He worries that his friends will think he’s ignoring them when, in fact, high fives are just outside his range of vision. The North Potomac teenager can see everything directly in front of him—but his peripheral sight is blurry. It’s like looking through a tunnel, he says, except with the edges blurred, rather than black.
Bobby, a junior, and his 15-year-old freshman brother, Danny, have retinitis pigmentosa, a genetic disease that affects about 100,000 Americans and gradually destroys the retina, sometimes resulting in blindness. Though the Macks were quite young when their parents learned they had the disease, it typically is diagnosed in adolescents and young adults.
The boys wear eyeglasses but stumble over objects on the ground and struggle to see at night, which made it difficult to negotiate their neighborhood on Halloween when they were younger.
They won’t ever be able to drive a car, and they face the possibility of losing their sight completely.
Lisa and Steve Mack say Bobby was about 3½ when they noticed how close he got to look at TV or objects on the ground. They hadn’t observed that kind of behavior in their older son, Andy, now 19.
They brought Bobby to a pediatric ophthalmologist who prescribed glasses. But during a follow-up visit, the doctor noted irregularities in the boy’s retina. She sent Bobby to a specialist, who diagnosed retinitis pigmentosa when the boy was about 4.
“I remember walking out to the parking lot and putting Bob in the car,” says Steve, 53, the financial operations manager at EMCOR Services Combustioneer in Rockville. “Lisa and I looked at each other in the parking lot like the life was snuffed out of us.”
There was no family history of eye problems, so when the doctor “started talking blindness, I was just in a total state of shock,” says Lisa, 48, an accountant at Marriott International in Bethesda.
They were advised to test Danny and Andy because of the genetic component. Andy didn’t have it, but Danny was diagnosed with the disease at about age 2.
Since then, the Macks have learned a lot about retinitis pigmentosa. The retina, which captures images for the eye, is made up of multiple layers. One of those consists of photoreceptor cells that perceive light and turn it into electrical signals.
One type of photoreceptor cell, the rod, is responsible for black and white and night vision; the other type, the cone, is responsible for daylight and color vision, says Dr. Stephen Rose, chief research officer at the Foundation Fighting Blindness, a Columbia-based nonprofit that works toward prevention, treatment and cures for retinal degenerative diseases. With retinitis pigmentosa, the rods and cones gradually die. In the Mack boys, as in most patients, the rods at the periphery of the retina were affected first.
“One of the first symptoms people will experience is they don’t see well at night and don’t do well in changes between light and dark,” Rose says. “Progressively, as the rods die, that’s where you lose your peripheral [vision] and you’re looking more and more like through a toilet paper roll or the binoculars through the wrong end.”
When the cones at the center of the retina start to erode, the person’s central vision and color perception begin to deteriorate. “Once these cells are lost, it’s very difficult to recover them,” says Dr. Wadih Zein, a clinician at the Bethesda-based National Eye Institute (NEI), part of the National Institutes of Health. By “difficult,” he means seemingly impossible: So far, scientists haven’t figured out a way to regenerate rods and cones, Zein says.
About 20 percent to 30 percent of people with retinitis pigmentosa go totally blind, Rose says. The majority continue to perceive light, though it may be indistinct.
There is no cure and no U.S. Food and Drug Administration-approved treatment for retinitis pigmentosa, Rose says. A 1993 study funded by the NEI and the Foundation Fighting Blindness suggested that Vitamin A could help slow the disease in some patients. The Mack brothers have been taking the supplement for about three years. The supplement’s efficacy hasn’t been proven in all cases of retinitis pigmentosa, although it has a positive effect in some people.
