Many people have had August 21 marked on their calendars for years. A total solar eclipse is a bucket list moment for millions of people, and while this event is an opportunity to experience a true wonder of astronomy, it also presents risk for eyes. Below are some tips optometrists can share with patients regarding viewing the eclipse safely.
The only safe time to view an eclipse without protection is during the couple of minutes when it is total. At all other times during the partial eclipse, proper eye protection must be worn to avoid damage to the eyes. The partial eclipse can be seen for about an hour before and an hour after the total eclipse.
The absolutely safest method of viewing an eclipse is to not look directly at it! View the image with a pinhole camera or projection; a web search can identify many sites with simple instructions on how to construct these. If you want to view the eclipse directly, get “eclipse glasses” that carry a certification that they comply with international standard ISO 12312-2:2015, or track down welder’s glass with Shade Number 14, the darkest available. Finally, do not use exposed film or x-ray film, a mylar balloon or food wrapper, smoked glass, or combinations of sunglasses or any other tinted lenses.
Looking directly at the sun for a few seconds at any time, even during a partial eclipse, will immediately result in a significant afterimage that can last for many minutes. Looking at the sun for a mere few minutes can result in permanent damage to eyes, leading to blindness, usually of central vision. This is known as solar retinopathy.
The solar eclipse will only increase in interest as we approach August 21. It’s our job as optometrists to ensure that our patients are educated to enjoy this event while also protecting their vision.