The solar eclipse that is due to occur on 12 August is one of the most highly anticipated astronomical events of the summer. Yet despite the interest it generates, ophthalmologists remind us that viewing it without proper protective measures can have serious consequences for eye health.
Dr José Lamarca, ophthalmologist and lecturer in the Faculty of Medicine and Health Sciences at UIC Barcelona, warns that looking directly at the Sun during an eclipse (total or partial), even for just a few seconds, may cause solar retinopathy, a lesion of the macula – the central area of the retina responsible for sharper vision – which in some cases may be irreversible.
“The retina has no pain receptors. This means that the person does not perceive that it is being damaged while looking at the Sun. When symptoms appear, the damage has already been done,” explains Dr Lamarca.
Not sunglasses; eclipse glasses, with caution
The specialist notes that conventional sunglasses, even of good quality, are not designed for looking directly at the Sun. “While sunglasses may darken vision, they can also dilate the pupils, which may allow even more radiation to reach the retina,” Dr Lamarca remarks.
Nor are other popular methods safe, such as looking through old X-rays or photographic negatives, as they provide a false sense of protection yet still allow a dangerous amount of solar radiation to pass through.
To safely observe the eclipse, it is essential to use certified glasses that comply with international standard ISO 12312-2. This certification must be clearly indicated by the manufacturer. It is also important to check that the glasses are in good condition – no scratches or defects – and that they are sourced by a reliable distributor. Even when using certified glasses, it is recommended to observe in short intervals and avoid fixing one’s gaze on the Sun for too long.
How to take photos safely
“Watching the eclipse through a mobile phone screen is safe. What can cause injury is looking directly at the Sun to frame the photograph while taking it,” Dr Lamarca notes. Likewise, the use of binoculars, telescopes or cameras with telephoto lenses without specific solar filters can significantly increase the risk of eye injury. In these cases, the filter should always be placed in front of the lens and never behind the eyepiece.
After observing an eclipse, the appearance of blurred vision, a dark spot in the centre of the visual field, distortion of straight lines or changes in colour perception may be signs of retinal damage. Dr Lamarca urges anyone experiencing these symptoms to see an ophthalmologist. Although some mild cases of solar retinopathy may improve over time, in other cases, damage to the macula is permanent.
“Watching an eclipse is an extraordinary experience, but it should only be done with proper protection. When it comes to the retina, prevention is always the best guarantee,” concludes Dr Lamarca.
