WASHINGTON (Reuters) – Millie Sauer did not even know she had suffered a stroke until she tried to read a book as she recovered from surgery and saw only a grey blur for part of the page.

Hours or even days had passed since the stroke had damaged part of her brain responsible for vision and Sauer, 69, was far past the point for any effective treatment.

"I was told I would have to live with my situation," Sauer, who lives in Sun City West, Arizona, said in a telephone interview.

But an experimental computer-based programme has helped Sauer regain some sight and given her hope of further recovery.

"We were very surprised when we saw the results from our first patients," said Krystel Huxlin of the University of Rochester Eye Institute in New York, who tested the system with seven stroke patients.

"This is a type of brain damage that clinicians and scientists have long believed you simply can't recover from. It's devastating, and patients are usually sent home to somehow deal with it the best they can."

Writing in the Journal of Neuroscience, Huxlin and colleagues said their approach used so-called blindsight – when a person with vision loss senses something they cannot actually see. "It is interesting that if you forced them to guess ... they can sometimes guess correctly. This is a phenomenon termed blindsight," Huxlin said.

Sauer and some other patients can drive, shop and live near-normal lives. "I think I have been able to live a pretty fulfilling life," Sauer said.

But it took months of staring at a computer screen to do so.

Strokes damage various parts of the brain and when the visual cortex is affected, the basic machinery involved in sight remains intact. The eye is taking in images – but the brain is incapable of processing them correctly. "A lot of neurologists and clinical practitioners are not aware that it is possible to regain vision after stroke," Huxlin said.