Dr. Ming Wang, Harvard & MIT (MD, magna cum laude); PhD (laser physics), presented the following Q&A for the public, for the solar eclipse on Mon 8/21 at 1:27pm in Nashville
1. Can I use my cell phone, to take a photo or a video, of the eclipse, or can I use a telescope?
Yes, but only if you do it in the right way.
First of all, camera or telescope actually concentrate, focus and amplify light intensity, hence, looking through these devices with naked eyes is in fact more dangerous than the naked eyes themselves.
The proper way of doing is to put the proper solar eclipse glasses IN FRONT OF the camera or telescope (i.e., the solar eclipse glasses are closer to the sun), and do not put the solar eclipse glasses directly on your face (and then look through your cell phone or telescope)
2. What will be symptoms, of solar eye damage and when do you typically occur?
They typically occur within a few minutes or hours. They symptoms are:
- Watery and sore eyes.
- Light sensitivity
- A blind spot in the center
- Things appear usually colored
- Things appear to be distorted and blurry.
- Cannot see details.
3. What should I do then?
See an ophthalmologist or optometrist, right away, since you may have suffered solar eye damage.
4. If I do, it is permanent?
Some are transient (resolving in 3-4 weeks), some (partial) sight loss can be permanent.
5. Can I just use my regular sunglasses?
No, they do not offer sufficient sun radiation protection since your regular sunglasses are designed for you to look INDIRECT sun rays REFLECTED from surfaces such as the road while you are driving. They are not designed, for you to safely look DIRECTLY AT the sun.
6. If I do use the proper sun eclipse glasses (ISO 12312-2, meeting international safety standard), can I look at the sun for extended period of time?
No. Even with the proper sun eclipse glasses on, you should only look at the sun for a very short duration (few seconds), and then, you have to turn your head away, rest for a while and then you can turn your head towards the sun again.
7. How can make sure that my kids are following the proper instruction about how to use the sun eclipse glasses?
You should put a pair of ISO 12312-2 solar eclipse glasses on them, first, and then, put them on for yourself, and then, ask you kids to do exactly what you will do.
8. What should I exactly do then?
- Put the sun eclipse glasses on.
- Turn towards the sun, but for only a few seconds.
- WHILE you are stilling wearing your solar eclipse glasses, turn your head away, and ONLY AFTER you have already turned your head away should you remove the solar eclipse glasses. Namely, please do not remove the solar eclipse glasses while you are still looking at the sun.
9. When can I actually look at the sun for more than few seconds each time, assuming I do wear ISO 12312-2 solar eclipse glasses?
You can look at the sun, for longer then a few seconds each time, ONLY during TOTAL solar eclipse (1:27pm-1:29pm, Mon 8/21, for Nashville).
10. How can I make sure that my solar eclipse glasses are in a proper shape to be used?
- Labelled ISO 12312-2
- Less than 3 years old.
- No scratch or damage on them.
11. What about my dogs and cat?
Keep them away from exposing to the solar eclipse altogether.
12. Does having had LASIK or cataract surgery (with UV-protecting IOL) help?
13. I have not had LASIK, and I am wearing glasses, can I look at the sun with my glasses?
No. One should never view solar eclipse through just regular glasses. In fact, if you do wear glasses, since you have to put the solar eclipse glasses on top of your regular glasses, this results in the situation in which now your solar eclipse glasses are futher away from your face, increasing the chance of solar radiation reach your naked eyes from the side. So in that sense, having had LASIK (and hence you are no longer wearing glasses) does offer slight advantage since you now can put the solar eclipse glasses directly on your face, minimizing the side gap.
Ming Wang, M.D., Ph.D.
Harvard & MIT (MD, magna cum laude); PhD (laser physics)