Experts have warned that looking directly into the sun during Friday’s solar eclipse could cause blindness.
Radiation emitted by the sun is so powerful it may cause solar burns of the retina, the College of Optometrists explains.
And the risk is just as high for those taking pictures – including selfies - of the eclipse.
Daniel Hardiman-McCartney, a clinical adviser at the College of Optometrists said: “The College advises against taking photos of the eclipse and this includes taking selfies.
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“Taking a selfie could potentially put you at risk as you may end up accidentally looking directly at the sun while aligning yourself and your phone. However viewing a video or photo of the eclipse on a phone screen would not be harmful.
“The safest way to view the eclipse is indirectly, for example on TV.”
The College also warns against looking at the eclipse even with sunglasses as they are not enough to avoid injury.
You are also putting your sight at risk if you view it directly through a telescope, binoculars or camera.
Speaking to the BBC, Hardiman-McCartney added: “In 1999, when there was the last major eclipse, no-one really had smartphones or took selfies.
"This could potentially be very dangerous because people might be tempted to look at the sun as they try to get the perfect shot or clip.
"And as the eclipse is a relatively slow process, people might end up accidentally looking at the Sun for minutes."
One way of viewing the eclipse is using a pinhole projection method, which involves putting a hole in a piece of cardboard, holding the cardboard up – with your back to the sun – so that an image of the sun is projected onto another piece of paper or card.
Another way of safely viewing the solar eclipse is to buy a pair of Solar Eclipse Glasses. Similar to 3D glasses, eclipse viewers are made from card and inlaid with a special material that cuts the Sun's light down 100,000 times. If using a viewer, check for holes or scratches as it is only safe if undamaged.
Eclipse viewers are being given away free with the Society for Popular Astronomy's members' magazine and the BBC's Sky at Night magazine. Here are some places with glasses still in stock. Ebay is another - though you may end up paying silly prices for them.
What is a total solar eclipse?