SOCIAL media users taking part in viral TikTok challenges are putting themselves at risk of blindness, an expert has warned.

Dr Nigel Best, an optometrist at Specsavers, is urging people not to take part in these trends which sees them exposing their eyes to bright lights and toxic substances.

He says: ‘These challenges can be extremely dangerous and can put your eye health at risk. It really isn’t worth jeopardising your sight for a sake of a few likes and shares on social media.’

One of the challenges going viral on the platform sees people mixing bleach, hand sanitiser, jelly and shaving cream in a bag and holding it up to their eyes. It is thought this will make them appear brighter – however this is not the case.

Dr Best says: ‘Simply don’t do it! Apart from the fact that it won’t make your eyes any brighter, if the bag splits and the contents leak out it could cause corneal scarring, extreme pain and blindness.’

Another video doing the rounds sees users trying to change their eye colour from brown to blue by exposing the eye to bright light while using the S5 filter on their phones. However, Dr Best says this could lead to permanent damage.

He says: ‘When exposed to bright lights we would naturally avert our eyes and our pupils would constrict. These two actions will reduce the amount of potentially harmful light falling on the retina.

‘By intentionally exposing your retinas to bright lights, you risk permanently damaging the light sensitive cells on your retina and causing blind spots.’

The ‘fingereyechallenge’ is also making appearances on people’s feeds, which while isn’t as invasive as the others, it could cause some damage.

It involves someone holding their finger over one eye while looking towards that finger with the opposite eye. Videos see them holding it in place for 10-15 seconds before moving their finger resulting in eyes temporarily pointing in different directions.

Dr Best says: ‘There are six different muscles controlling the movement of each eye and it only requires one of these 12 eye muscles to become misaligned for any reasons for a squint and double vision to occur.

‘Optometrists will sometimes use tests similar to the finger challenge to test the strength of the eye muscles but in a very controlled and safe way. We would advise against people carrying out these tests on themselves as it could result in eye strain and temporary double vision.’

There are 9 Specsavers Ópticas stores in Spain, in Marbella and Fuengirola on the Costa del Sol, Santa Ponça in Mallorca and Javea, Calpe, Benidorm, Torrevieja, Guardamar and La Zenia on the Costa Blanca. Visit www.specsavers.es to find your nearest store or book an eye test.