A legally blind Toronto-area man discovered he had a common condition that was causing him to see bizarre, fanciful images that weren't real.

Jack Hunter began losing his vision several years ago, and has suffered glaucoma, cataracts and muscular degeneration.

Hunter is legally blind, but started to experience visual hallucinations.

"I saw what appeared to be a woman, and she was mopping the floor," he told CTV Toronto.

He also saw a bee or a wasp flying around a man's head.

"I thought, 'Why isn't he swatting at that thing?'"

But then Hunter realized the insect wasn't real. He started to research, and learned he was experiencing Charles Bonnet syndrome (CBS), a common condition among people who have lost their sight.

Named after a Swiss botanist, CBS causes visual hallucinations several times a day. Those with CBS often question their sanity.

However, CBS is not a mental illness, nor is it a symptom of dementia, according to the Canadian National Institute for the Blind. (http://www.cnib.ca/en/your-eyes/eye-conditions/Pages/Charles-Bonnet-syndrome.aspx)

Generally, people experiencing CBS hallucinations are aware that what they're seeing isn't real. They can last for a few seconds to several minutes.

The CNIB said the condition is very common, but that public awareness is limited so it often goes undiagnosed.

A recent CNIB study showed that approximately 20 per cent of the organization's clients had suffered some form of hallucinations.

The symptoms usually leave within 18 months of vision loss, but it is not unusual for CBS to last for five years or more.

The syndrome occurs only in people who had vision at one point, and is the brain's attempt to fill in the images they can no longer see, the CNIB's Dr. Keith Gordon told CTV.

The CNIB said the hallucinations can be "distressing," and range from simple shapes and lines to people and animals.

Some can get the hallucinations to go away by looking directly at the image, changing the lighting or moving their body, Gordon said.

Hunter said he blinks rapidly without moving his head, and that helps the hallucinations disappear.

The organization's website said there are many accounts of complex hallucinations, including "little men holding umbrellas at the end of the bed," and "women in red dresses sweeping the floor."

Those who have lost some of their vision to conditions including macular degeneration, glaucoma and diabetic retinopathy may be at risk, the CNIB said.

Anyone who thinks they may be suffering is encouraged to see a doctor, and make sure the doctor knows that they've recently experienced vision loss.

With a report from CTV Toronto's Pauline Chan