PASADENA ( — A Pasadena man went to bed with normal vision, then he woke up half blind in one eye. Now he’s part of an international research study to treat what doctors call “Stroke of the Eye.”

Peter Tamny suddenly had trouble seeing out of his left eye that morning.

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“It comes on and you don’t even know it, you don’t feel any pain,” Tamny said. “I did what everyone does I put eye drops in and went to work.”

But things rapidly got worse.

“I couldn’t read the newspaper I couldn’t read the computer.”

Two ophthalmologists couldn’t figure out what was wrong. They sent the 73-year-old to neuro-ophthalmologist Dr. Peter Quiros, of the Doheny Eye Institute UCLA.

He diagnosed him with ‘Stroke of the Eye.”

“It’s an interruption of blood flow to the optic nerve,” Quiros says. “It’s really sudden, painless vision loss when people wake up in the morning.”

Dr. Quiros says symptoms usually get worse in two or three days and some patients lose vision completely within weeks.

“This disease is the most common optic nerve disorder in patients over 50,” Quiros says.

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Still Quirios says it’s often misdiagnosed and time is critical.

There is currently no treatment. The doctor enrolled Tamny in an experimental drug study with at least 200 other patients around the world. Treatment has to be given in the first two weeks of onset.

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“It blocks a cellular messenger that normally tells cells to die,”Quirios says.

Some patients are receiving the placebo, and it’s too early to tell if there’s improvement,”

“If I close this eye, this eye doesn’t see as well and I can’t read his shirt which I can with this eye,” Tamny said.

Tamny is hopeful his story sheds a light on what’s been a dark spot for him.

“You have to see your doctor immediately mainly because the cells dying in optic nerve, they start immediately,” Tamny says.

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The study will go for about another year.