Toronto, Apr 8 (IANS): Regular use of viagra, used to treat erectile dysfunction, can harm your vision leaving you blind, a study has claimed.

Researchers from the University of British Columbia in Canada have found that people regularly taking the common erectile dysfunction pill may be at increased risk of sudden losses of vision, flashes of light, and dark spots, Daily Mail reported.

The reason may be an increase in blood flow to the genitals which could be hindering its supply to the eyes, the researchers said.

The team also named other impotence medicines - Cialis, Levitra and Spedra - as being potential triggers of eye problems.

Regular users of the impotence pills are 85 per cent more likely to develop serious vision-robbing conditions, revealed the study published in JAMA Ophthalmology.

"These are rare conditions, and the risk of developing one remains very low for any individual user. However, the sheer number of prescriptions dispensed each month in the US - about 20 million - means that a significant number of people could be impacted," lead researcher Dr Mahyar Etminan, an ophthalmologist at the varsity, was quoted as saying.

"Regular users who find any changes in their vision should take it seriously and seek medical attention," he suggested.

In the study, the team analysed insurance claim records of 213,033 men using ED pills: 123,347 men took sildenafil - the medication branded as Viagra by Pfizer, 78,609 were on tadalafil (Cialis); 6,604 took vardenafil (Levitra), and 4,473 were on avanfil (Spedra), the report said.

The team followed the claim records from 2006 to 2020 to see which ones went on to develop eye conditions. None of the men had suffered eye problems in the year before they became regular users of the medication.

They found that regular intake of one of the medications was 158 per cent more likely to lead to serious retinal detachment. It occurs when a collection of fluid builds up behind the back of the eye and causes the sudden appearance of spots in the field of vision and flashes of light.

The men were 102 per cent more likely to suffer ischemic optic neuropathy - a compromised blood supply to the optic nerve. The condition causes a loss of central vision. And they were 44 per cent more likely to develop retinal vascular occlusion - a type of blood clot in the retina. People with it suffer a sudden loss of vision and dark spots or 'floaters' in their vision, the report said.