Someone correct me if I'm wrong, but I don't think a camera flash can actually cause blindness or permanent damage to a glider's eyes. Yes, it can be uncomfortable for them since their eyes are "geared" for nighttime. And it can cause temporary after-images just like it can in humans, but I don't think the type of light used for a camera flash is capable of either burning retina or damaging the cornea or lens.

Now sunlight is a different story. I do believe sunlight can cause cataracts and even retinal problems in gliders because it can do that over time in humans. The reason is that sunlight includes UV wavelengths, while camera flashes don't.

I think a glider's sensitivity to light is similar to that we would have when our pupils are dilated with drops for an eye exam (you know how you have to wear those funky sunglasses when you leave the office).

If you know of any credible studies or articles that say differently, please correct me, and direct me to them if possible. I am basing my comments on my experience as an eye doctor on people. I am new to gliders and am unaware of glider-specific research on this topic.

[:"green"]PeeperKeeper,
I totally agree with your logic. I have been taking pictures of my gliders for years and have not had any problems develop because of it. They also don't really seem to mind at the time of the pictures being taken. I usually take their pictures during the daytime when their pupils are almost completely contracted anyway, so there is very little light getting through to begin with. Although I'm not an eye doctor, I am an ABO certified optician and I know that your facts as stated above are correct about humans... Thanks for the great information! <img src="/ubbthreads/images/graemlins/hug2.gif" alt="" /> <img src="/ubbthreads/images/graemlins/hug2.gif" alt="" /> <img src="/ubbthreads/images/graemlins/hug2.gif" alt="" /> [/]

This isue comes up about twice a year. The best explanation of this topic was given by Pepony about two years ago.
Bottom line. YES. A camera flash CAN cause retina and pupil damage if the picture is taken closer to the subject and if there is a continious series of flashes. Most cameras used for domestic use (point and shoot cameras) have a mild powered flash and you would have to do a heck of alot of shooting to cause any damage. You probably will run out of battery before you cause any damage. In some cases, when you use an SLR with an flash attachement, these flashes (they usualy take 4 AA batteries) may be slightly stronger and could cause the damage at a faster rate, but once again, you would have to shoot a heck of alot of pictures.
If Pepony can be reached, I believe he has the same explanation with more details and all the calvin ratios and decivels of light wave and harmonics...but he has the time to study all that and share it with all of us....I only have time for REAL photography!

(sorry Pepony,,,could not resist picking on you!)

Heres a good article, I thought, on Flash Photography and the Visual System of Birds and Animals <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />

Really? This just comes up twice a year? I'd think it would be a constant topic because every time somebody new to gliders wants to take pictures of their new pet, they'd take one look at those big nocturnal eyes and think twice. Thanks for the input everybody.

Gil, your info makes sense as well. Non-UV light can cause damage in large enough doses. People sometimes ask if the light from the microscope we use in an eye exam (just a regular incandescent) can harm their eyes. The answer is that in the way that we use it, it can't. But if we were to use a lens and focus on one place on the retina with the light at full blast and hold it there for several minutes (which would be very difficult to do, just because of the average person's eye movement), it could possibly cause some damage. Before anybody starts getting worried that at their next exam when the doctor is looking at the back of the eye s/he is going to hurt the eye, I'm talking about a much longer period of time than we might take during an exam, even if we are looking carefully at something back there.

Just FYI, my camera has a regular and low setting for the flash, and I always keep it on low.

<img src="/ubbthreads/images/graemlins/offtopic.gif" alt="" /> SGSuz cool! We're in the same line of work! How long have you been "opticianing"?