When people talk about the August 12 eclipse, almost all the conversation revolves around practical matters: schedules, special glasses, and the best places to view it.
But behind that excitement lies a very serious warning from experts such as Professor Alfredo García Layana, an ophthalmologist and president of the Spanish Society of Retina and Vitreous (SERV): “Looking at the Sun without proper protection—even during an eclipse— can cause a silent burn to the retina. This damage occurs in a matter of seconds and, in many cases, leaves irreversible consequences.”
The damage occurs in seconds, even if there is no pain
The first point García Layana emphasizes is that there is no “safe time” to look directly at the eclipse. The risk depends on several factors—light intensity, the Sun’s altitude, the use of optical instruments, and the duration of direct viewing—but the margin is minimal: damage can occur in a matter of seconds if the Sun is viewed directly without proper protection. Solar radiation concentrated on the retina causes what is known as solar retinopathy, a condition that destroys light-sensitive cells.
He asserts that these cells do not regenerate. Therefore, the consequences can be permanent, including loss of central vision, spots in the visual field, and difficulty recognizing fine details. The ophthalmologist is unequivocal in his recommendation: “If you’re going to look at the Sun, it’s prudent never to remove the special protective glasses approved for eclipses.”
Eclipse glasses: what it means to be certified
Faced with the flood of products being advertised these days, García Layana insists on an objective criterion: the glasses must comply with the international standard ISO 12312-2, which is specifically designed for direct observation of the Sun. That reference must be printed on the product. Not just any sunglasses will do, no matter how dark or expensive they are, nor will homemade contraptions such as X-rays, tinted glass, or CDs.
The ophthalmologist recommends purchasing the glasses from trusted distributors, specialized centers, or scientific institutions, and being wary of products without clear labeling or of dubious origin. Before using them, it’s important to check that the filters have no scratches, holes, or damage. Even a tiny tear can be enough for radiation to enter right through the weakest spot.
Total or partial? The risk is almost the same
Regarding the difference between total and partial eclipse zones, García Layana clarifies an important point. During a partial eclipse, you should never look directly at the Sun without protection, because part of the solar disk always remains visible and its intensity is still sufficient to damage the retina.
During a total eclipse, there is one very specific exception: only during the seconds of totality—when the Moon completely covers the Sun’s disk and only the corona is visible—can you look at it without special glasses. As soon as the first flash of light appears at the end of totality, it is essential to protect your eyes again immediately. Outside of that very brief interval, the risk is exactly the same as during a partial eclipse. Therefore, their practical advice is that if you are going to look directly at the Sun, the safest option is to keep your eclipse glasses on at all times.