Optic nerve edema not always treatable

Issue: April 2018

ATLANTA – Nonarteritic ischemic optic neuropathy and optic neuritis are two of the most common types of optic nerve edema, according to Trenton Cleghorn, OD, here at SECO, and neither can or necessarily need to be treated.

Ischemic optic neuropathy is the nonarteritic type 95% of the time, he said, and one cause could be sleep apnea.

“If a patient doesn’t have risk factors, ask about this,” Cleghorn said. “Get them to a sleep specialist. This is not a benign condition.”

He said some refer to nonarteritic ischemic optic neuropathy (NAION) as “overnight normal-tension glaucoma.”

“Some people believe normal-tension glaucoma and NAION are the same conditions, but NAION is just sped way up,” he said. “We suspect we get NAION because of nocturnal hypotension when pressure goes down at night and up during the day.

“Patients wake up and can’t see,” he continued. “They shouldn’t have any other eye symptoms, no pain or headache. Disc pallor takes 3 to 6 weeks to occur, and it is usually bilateral.”

NAION can be caused by hypertension, diabetes mellitus, high cholesterol, coagulopathy and obstructive sleep apnea. Cleghorn said patients should be imaged if there is no vascular disease.

“This is a sad condition,” he said. “There’s really nothing you can do that’s been proven to work for this. We’ve tried blood thinners, brimonidine for neuroprotection. All we can do is figure out what’s going on and cut down on your risk factors.”

Cleghorn noted that up to one-third of cases can be progressive. He said he tells patients that their vision may not get any better than it is right now, but there is a small possibility.

He said the other “big player” is typical optic neuritis, which is usually unilateral and usually happens in younger women, ages 15 to 45 years. Vision can be 20/20 to no light perception.

“You hear the classic, ‘pain on eye movement,’” Cleghorn said. “It could be retrobulbar orbital pain. They may have vision issues like color vision and contrast.”

Nearly two-thirds of the time the optic nerve looks normal, he said.

“It’s tough to diagnose,” Cleghorn said. “Usually when there is edema it’s very mild, and they have more of a hyperemia; you may have some hemorrhages. Check color vision for afferent pupillary defect. If you have optic neuritis there will be something going on – visual field defect, color vision, relative afferent pupillary defect.”

Cleghorn said two-thirds of women with optic neuritis will develop multiple sclerosis, while only one-third of men will.

He said to look for white matter lesions in the brain on MRI.

“MRI the orbits to see inflammation back there, too,” he added. “It is not necessary to have an MRI for the optic neuritis; it’s more for the MS component,” he said.

Change in white matter lesions on MRI, family history or neurological symptoms warrant referral to a neurologist, Cleghorn said.

Visual-evoked potential is helpful when there is retrobulbar neuritis to see latency or a reduced signal, he said.

Cleghorn said most patients with optic neuritis get better on their own. Results from the Optic Neuritis Treatment Trial showed that the use of steroids did not improve final visual acuity; however, it hastened recovery.

“Ninety-three percent of patients with or without treatment were 20/40 or better, but steroid speed up recovery of vision,” he said.

“In a patient where it’s not contraindicated, you definitely want to offer it,” he said. “Oral steroids on their own made patients worse. You want high-dose methylprednisolone IV for 3 days followed by oral prednisolone.”

Cleghorn explained that high dose oral steroids – 1,200 mg – can be compounded into a “slushy” with orange juice.

“Patients should either go into the hospital or try the compounding pharmacy,” he said.

He said the treatment will make patients feel bad, but only for a few days. Younger, healthier patients tend to tolerate it better. – by Nancy Hemphill, ELS, FAAO

Disclosure: Cleghorn reported no relevant financial disclosure.