With the solar eclipse approaching, eye safety experts are warning that uncertified or fake viewing glasses could cause serious retinal damage. The eclipse, set for August 12, will see more than 90% of the Sun blocked by the Moon between 6.17pm and 8.06pm, making it the most spectacular astronomical display since the total eclipse of 1999.
Only Certified Glasses Are Safe
Experts stress that only solar eclipse glasses carrying ISO 12312-2 certification should be used for safe viewing. However, these have virtually sold out online, with remaining stock often subject to steep delivery charges to arrive in time.
Specialists have strongly cautioned against using uncertified eclipse glasses or ordinary sunglasses, regardless of how dark the lenses are. While such eyewear reduces glare and makes it feel more comfortable to gaze at the Sun for extended periods, harmful solar radiation can still penetrate the retina.
Risks and Symptoms
Following the 1999 total solar eclipse, the Royal College of Ophthalmologists recorded approximately 70 cases of vision problems amongst viewers. Around 40% had looked at it for less than a minute.
Mohamed Elalfy, a consultant ophthalmologist and president of the Royal College of Ophthalmologists, warned: "The safest way to enjoy the eclipse is to observe it indirectly, such as by watching a live broadcast. Looking directly at the Sun during a solar eclipse can cause damage to the retina, potentially damaging the cells responsible for sharp central vision."
"Crucially, the retina has no pain receptors, so people will not feel the damage as it happens. Symptoms may only become apparent several hours later and can include blurred vision, a central blind or dark spot, distorted vision, reduced colour perception and increased sensitivity to light."
"While some people recover over weeks or months, others can be left with permanent visual impairment."
Advice for Parents and DIY Filters
Kyla Black, Boots Opticians director of optical practice, urged parents to be "particularly careful" letting their children view the eclipse, and warned that certain homemade filters can pose a serious risk.
"If you're purchasing specially made eclipse glasses, make sure to double check that they are undamaged before use as even a glimpse of damage could have an impact on your eyesight," she said.
"It's a common myth that wearing multiple pairs of sunglasses can protect you from any harmful UV light – this is untrue and should be avoided at all costs as only purpose-built eclipse glasses can allow you to watch an eclipse."
Ms Black continued: "Although a fun idea for many may be to make DIY filters and pinhole projectors out of cereal boxes, this can also be dangerous. Objects such as smoked glass, colour film, floppy disks, X-ray film, and dark sunglasses are unable to block invisible infrared and ultraviolet rays, potentially leading to damage to your eyesight."
Safe Viewing Methods
Budding astronomers who will be looking through cameras, binoculars or telescopes at the eclipse must make sure they have approved solar filters attached. If you're not sure your telescope does, then contact the maker of the product to ensure you know you'll be safe.
The Royal Observatory Greenwich has also cautioned members of the public that ordinary sunglasses do not provide adequate protection for viewing the celestial event.
Imo Bell, a planetarium astronomer at the observatory, previously told the Press Association: "It's not a total eclipse, but over 90% is really exciting. We're not going to get one this good for a really long time."
"So, it's important not to miss it, and to be prepared. You can't just go out and expect to have a look, because it's really dangerous for your eyes."
"So, you can use solar eclipse glasses, which are very, very different from sunglasses – they block out so much light that you can't see anything through them except the Sun, because that's how much light they need to block for the damaging light of the Sun to be safe to view. Ideally a solar telescope is an amazing way to witness it, and if you don't have one of them then you can look into whether your local astronomy society is doing any events."
"And if all else fails, you can project the image of the eclipse using a household item like a colander which has lots of holes in – point the colander towards the Sun with your back facing it, and in the shadow of the colander you'll be able to see the eclipse in the holes, which is really cool."
As an extra treat for astronomy enthusiasts, the yearly Perseid meteor shower hits its zenith on the evening of August 12-13. The display occurs as our planet passes through debris trails left by Comet Swift–Tuttle. Every minuscule particle collides with Earth's atmosphere at approximately 60 kilometres per second, incinerating in a momentary burst that resembles a shooting star.
