Amy Epstein Gluck with her son Sam. To sharpen his vision, he wears contact lenses rather than glasses. (FAMILY PHOTO)

Amy Epstein Gluck remembers how relieved she felt when it seemed that the vision of her youngest child, 9-month-old Sam, might turn out to be normal.

Months earlier, doctors had worried that he was blind, possibly as the result of an inherited disorder or a brain tumor. But subsequent tests and consultations with pediatric specialists in Washington and Baltimore instead suggested a temporary developmental delay.

Epstein Gluck and her husband, Ira Gluck, were so thrilled with Sam’s progress that they threw a big party to celebrate the end of an arduous year and, they hoped, their son’s frightening problem.

But two months later, on Sam’s first birthday in February 2006, the pediatric ophthalmologist who had been treating him delivered news that made it clear a celebration had been premature.

“It was such a blow,” Epstein Gluck recalled. On the way to Johns Hopkins, the couple had discussed finding a specialist closer to their Bethesda home, assuming they no longer needed a neuro-ophthalmologist. The ride home was somber: “I was so upset I couldn’t even recount the conversation,” she said. “I had thought we were done.”

Instead, they were struggling with the implications of an unexpected finding that, more than a year later, would culminate in a new diagnosis.

In March 2005, when Sam was about 5 weeks old, his mother noticed that his eyes would periodically oscillate back and forth. Epstein Gluck, whose other children were then 3 and 5, called her pediatrician.

“I wondered if it was a seizure, but it didn’t seem to affect him in any other way, so I didn’t get too concerned,” she recalled. Sam’s eyes also seemed not to be focusing, “but you don’t really think about that in a young baby anyway,” she said. An unfocused gaze is normal in the first months of life, as an infant’s ability to see matures.

When the pediatrician saw Sam, Epstein Gluck recalled, she examined his eyes for “a really long time,” then put her hand on his mother’s arm. The rapid, involuntary eye movements were caused by a condition called nystagmus, which is often temporary and not necessarily worrisome, although it can indicate more serious problems. In infants, nystagmus can be caused by abnormal functioning in the brain; sometimes the cause is unknown.

‘I don’t think he can see’

But the pediatrician was worried about something much more ominous than rapid eye movements. “I don’t think he can see,” she told Epstein Gluck.

The pediatrician immediately telephoned a pediatric ophthalmologist, who saw Sam a few hours later. The specialist concurred: Sam couldn’t see, although anatomically his eyes appeared to be normal.

One of two diagnoses seemed most likely, she said: Sam might have Leber congenital amaurosis, a rare eye disorder of which nystagmus is a symptom. If he had Leber, he would be blind. The second possibility was delayed visual maturation, which can have multiple causes. In the most benign scenario, a baby’s vision may simply be slow to mature.

There was little to be done, she added. It might take up to a year to tell whether Sam was blind.

The ophthalmologist “said to go home and come back in three weeks,” Epstein Gluck recalled. “I thought, ‘How can she tell me to go home and wait for three weeks?’ ” Instead she called her pediatrician, who helped her get an urgent appointment with an eye specialist at Washington’s Children’s National Medical Center.

There, a new and more frightening possibility emerged: Doctors worried that Sam’s vision problems might be the result of a brain tumor pressing on his optic nerve. An MRI scan found nothing. Doctors also performed an electroretinogram, which measures activity in the retina. The test showed that there was no movement in retinal cells, but that finding did little to clarify a diagnosis; in children as young as Sam, such tests tend not to be definitive.

Epstein Gluck, a lawyer, was deeply unsettled when she learned that the Children’s doctor — who also thought the problem was Leber or delayed visual maturation — rarely saw children with problems like Sam’s. “I wanted someone with more experience,” she said.

She e-mailed everyone she knew looking for a new specialist and was referred to Michael Repka, a pediatric neuro-ophthalmologist at Johns Hopkins’s Wilmer Eye Institute.

Repka first saw Sam when he was 2 months old. “The problem at that age is that there are a lot of things that might be going on, and the retina is not mature,” Repka said. Sam, he recalled, had “almost no visual responsiveness. He didn’t lock onto faces” or look at toys. “And if you shine a bright light, any self-respecting baby will close their eyes,” he said. Sam did not.

Repka told the Glucks he doubted that Sam had Leber or was blind, because his eyes moved. Delayed visual maturation was possible, but it is a diagnosis made after other disorders have been eliminated. Buoyed by his expertise and manner, Epstein Gluck said she felt comfortable waiting several months to see if Sam’s vision improved and then returning to see Repka.

In the meantime, she called Montgomery County’s Infants and Toddlers Program, which provides early intervention services to children with disabilities. The program dispatched two in-home therapists to work with Sam and help stimulate his visual and physical development by using toys and a medicine ball.

Slowly but steadily, it became clear that Sam was able to see. He began picking up toys, staring into faces and would blink in bright lights.

At 8 months he went back to Repka for a third visit. “His vision had improved markedly,” Repka said, “but it was not normal.” Time would tell whether his problem was merely delayed visual maturation.

Epstein Gluck said she and her husband, relieved that Sam could see and thinking “we had dodged a bullet,” made plans for the December celebration; the next appointment with Repka was scheduled for Sam’s first birthday in February 2006.

Unexpected news

“Well, he’s nearsighted,” Repka said after he examined Sam, measuring among other things, preferential looking time, the phenomenon in which an infant gazes longer at a new or unexpected picture or object.

How nearsighted? his mother asked. “Horribly nearsighted,” Repka replied.

Repka explained that Sam’s vision was a minus-7, which is considered highly myopic, a condition that affects about 2 percent of the U.S. population. Based on his test results and history, Repka said he suspected that Sam might have X-linked congenital stationary night blindness, or CSNB, a retinal disorder that causes nystagmus, severe nearsightedness and great difficulty seeing in low light. If this was Sam’s problem, it would become more evident as he became more mobile.

Epstein Gluck was stunned. “It felt like a punch in the gut,” she said.

CSNB is caused by a rare genetic mutation that affects cells in the retina, the tissue at the back of the eye that detects light and color. Females who inherit the defective gene are carriers but typically show no symptoms, unlike males. The prevalence of the disorder, which is present at birth, is unknown, according to Genetics Home Reference. Epstein Gluck said she knows of no other cases in her or her husband’s family.

Other than correcting vision with glasses or contact lenses, there is no treatment.

At 18 months, Sam got his first pair of glasses — little round Harry Potter spectacles. Two days later he began walking.

But as he grew, it was clear that Sam’s night blindness was growing worse and CSNB was more likely: During his first Halloween at age 21 / 2, while trick-or-treating with his older sisters, he fell into a shallow trench and walked into bushes.

In the middle of one night, he awoke screaming in fear. His father had accidentally turned off the light outside Sam’s room that was kept on all night and enabled him to see.

A second electroretinogram, performed in 2007, showed that his myopia had worsened — his prescription was minus-8.5 — but his retinas had remained intact. His current prescription is minus-11.25, and a test performed last month found that his retinas were stable. Now 8, Sam wears contact lenses, which allow him to see more clearly than glasses would, according to Repka.

Repka, who continues to see Sam, said he was cautiously optimistic. “It’s not progressed as much as I would have feared,” he said.

Although Sam’s condition requires accommodations, he has compensated and is not self-conscious about his eyesight. If he gets out of a car at night, a streetlight is not bright enough to allow him to see.

Recently he spent a month at overnight camp in North Carolina — “I sent him with two headlamps,” his mother said — where he learned to sail and water-ski and generally had a blast.

“We feel tremendously lucky, even not knowing how things will go in the future,” said Epstein Gluck, who tries to avoid the what-ifs. “I’m just glad Dr. Repka doesn’t scare me with what the possibilities are.”

Have a solved medical mystery? Send it to medicalmysteries@­ Check out other cases at