Primary congenital glaucoma, though relatively rare, is the most frequent childhood glaucoma and is an important cause of blindness in children worldwide. It shares many of the features of a disease that is common in older adults: elevated IOP, optic nerve damage and visual field loss. Yet the approach to therapy and long-term management of PCG reveals a general truth of pediatric medicine: Kids cannot be treated like miniature adults.
Given the infrequency of the disease —it occurs in about 1 in 10,000 births —most ophthalmologists may never encounter a child with glaucoma. “It’s a rare condition in the United States,” said Sharon F. Freedman, MD, associate professor of ophthalmology and pediatrics at Duke University and one of a handful of pediatric glaucoma specialists in this country. “But such a patient may walk into your office tomorrow.”
An ophthalmology resident could spend three years in training and never encounter a single case, said David S. Walton, MD, clinical professor of ophthalmology, Harvard University. So physicians encountering PCG should not hesitate to seek support. “Refer the patient or consult others who are familiar with the childhood glaucomas,” Dr. Walton said.
Andrew G. Iwach, MD, associate clinical professor of ophthalmology at the University of California, San Francisco, agreed. “Treating congenital glaucoma can be very labor intensive, very time consuming,” he said. “You need a team approach.” The team may consist of a glaucoma specialist with the skills to perform angle surgeries for congenital glaucoma, a pediatric ophthalmologist and the staff to help with patching or contact lenses that may be required.
Origins and symptoms. PCG is a hereditary condition, resulting from abnormality of the trabecular meshwork, possibly due to a developmental arrest, causing increased resistance to aqueous outflow. It accounts for approximately 55 percent of primary pediatric glaucomas.
Photophobia, epiphora and blepharospasm are hallmarks of the disease. In many cases, the cornea appears enlarged and cloudy from an overburdening of the corneal endothelium. “Any time I hear a parent say, ‘My kid has such big, beautiful eyes,’ that scares me,” Dr. Iwach said.
Though it’s a rare condition, “you want to have a high index of suspicion,” when those symptoms occur, said Terri Pickering, MD, a pediatric ophthalmologist and associate of Dr. Iwach at the Glaucoma Center of San Francisco.
Treat These Kids, But Not Like Adults
Unlike adult glaucoma, where drugs are the first-line treatment, children with PCG should be considered for surgery first, with drugs as a last resort. “Medications typically don’t work and tend to have more side effects in children because their enzyme-metabolizing systems aren’t as well developed,” said Dr. Pickering.
“If it’s truly primary congenital glaucoma, there’s a good chance that after one or two goniotomies, the child may have normal pressures and only need to be monitored, and will lead a full life,” Dr. Iwach said.
When the cornea is clear enough to enable confident viewing of the filtration angle, goniosurgery is the first-line surgical treatment for children with PCG. Alternatives are trabeculectomy and drainage tubes. As Dr. Walton noted, “Goniosurgery needs to be seriously considered for every patient. Exceptions to that may be newborns with severe angle defects and with corneal opacification,” explained Dr. Walton, who treats those patients with tubes.
Don’t go it alone. Dr. Iwach, who describes himself as “passionate” about goniosurgery, cautioned that it is “very delicate surgery,” requiring “two surgeons, four hands,” as well as special lenses and knives.
Dr. Freedman echoed that concern. “A pediatric ophthalmologist who hasn’t done one in three years probably shouldn’t be doing it. Or an adult glaucoma specialist who hasn’t done a patient under 25 probably should partner with someone who works with kids. You want to partner with, or hand off to, someone who is comfortable with this surgery in children.”
“It doesn’t always work, but when it does, it’s a great home run,” said Dr. Iwach. “It provides significant lifelong advantages over filtering surgery or setons.”
In fact, relapse following successful goniotomy is unusual, and normalization of IOP persists. “I’ve followed children one year after, five, 10, 15—they’re cured,” Dr. Walton said. “They’ve never seen an eye drop.”
Follow up that amblyope. The glaucoma may be cured, but these children are at high risk for amblyopia. In fact, much of the vision loss in these patients isn’t from glaucoma, but from amblyopia, Dr. Walton said.
Dr. Freedman added, “I’ve seen kids with beautiful pressures, but who have an eye legally blind from amblyopia.” Most doctors, unless they are accustomed to working with children, become so focused on intraocular pressures that they might forget to check for amblyopia, she said.
“The bottom line: This is a team approach,” said Dr. Freedman. Ideally, a child with glaucoma who is under the age of 10 should be cared for by a pediatric glaucoma specialist, she said. But given that there are only two or three dozen in the country, the team might consist of either a pediatric ophthalmologist or a comprehensive ophthalmologist with pediatric experience, together with a glaucoma specialist. A family practice pediatrician might also be in the loop.
The ophthalmologist must feel confident examining children. “Development of examination skills is very important,” Dr. Walton said. That means being able to measure eye pressures and assess the anterior segment in patients who can be rambunctious. “In some sense, it’s the most mundane expectation, but the hardest thing often is to get a good eye pressure measurement.” He added that IOP in a struggling child may be falsely elevated, and conversely low in an anesthetized child, but that mild sedation should not affect eye pressure.
Long lives for little eyes. Finally, there is a range of issues that might not occur to an ophthalmologist, “if they’re not thinking from the little person’s point of view,” Dr. Freedman said. You have to think about sports and fun and social activity, and the attendant potential for eye injury in kids already at risk for visual impairment. “It’s not good enough to say, ‘You’re 20/20 and your pressure’s good.’”
“It’s really important, because these children have so many years of life ahead,” Dr. Walton said. “You’re working for and giving each child a lifetime of vision.”
|Delays Can't Stop This Sand Castle Builder|
The strong chance for a cure in congenital glaucoma makes delayed diagnoses very frustrating to experts like Dr. Walton. One such case involved Sophia Vilim, who came under Dr. Walton’s care but not until she was diagnosed at age 2½.
Sophia’s mother, Claudia Vilim, recalls when she first noticed that anything was wrong. “One morning Sophia woke up and her eyes were bright red. She was probably four to six months at that point.” Sophia’s pediatrician diagnosed conjunctivitis and blocked tear ducts. “The pediatrician thought it was something common and would go away,” Ms. Vilim said.
An ophthalmologist correctly diagnosed primary congenital glaucoma, but by then Sophia was over 2 years old, and the condition was advanced. Sophia went to a specialist in Chicago, but even the specialist, who sees about 30 children a year with glaucoma, referred her to Dr. Walton.
After several goniotomies, Sophia’s pressure, without eye drops, has been controlled in both eyes now for almost four years. Even so, because of the delayed diagnosis, Sophia, who is now 6 and in kindergarten, has best corrected vision of 20/300 and some field restrictions.
Now, there is an opportunity for physicians to learn about the care and treatment of children with glaucoma through a fellowship with Dr. Walton and the glaucoma service at the Massachusetts Eye and Ear Infirmary. Teresa C. Chen, MD, is associate preceptor for the fellowship. For more information, Dr. Walton can be contacted at 617-227-3011.