Incidence of optic nerve hypoplasia, once rare, is on the rise

The congenital condition optic nerve hypoplasia, once considered rare, is being seen in increasing numbers, according to a report in the Wall Street Journal. Not much is known about the cause of the disease or why more cases are being seen now than in the past. Studies are under way to try to understand the etiology of the condition, which is often linked to serious systemic disorders.

The number of diagnoses of optic nerve hypoplasia (ONH) has risen since the 1970s, said Mark Borchert, MD, a pediatric neuro-ophthalmologist at the University of Southern California who is quoted in the Journal article. The condition is marked by the underdevelopment of optic nerve, with a small optic disc visible on ophthalmoscopy. Vision may or may not be affected.

Dr. Borchert is conducting a national study to learn about the demographic distribution of ONH, according to the article — whether, for instance, it is evenly distributed or occurs in clusters. He told the Journal he believes environmental factors may have contributed to the rising incidence.

In the past, ONH may have been misdiagnosed as visual impairment, according to the article. But in as many as 50% of cases the condition is associated with other neurological disorders. Patients may suffer from seizures or be unable to regulate body temperature or produce certain hormones, the report said. Diagnosis in the first months of life is crucial in some cases.

Although awareness of ONH is increasing, not many people know about the condition other than ophthalmologists and the growing numbers of families affected, the Journal report said. Attention was drawn to ONH in England when a celebrity there gave birth to a child with the condition, the article noted.