Can you have too much UVA light?

[Mr.Puff]

My baby Hermann's has been keeping his eyes closed a lot. Is it possible that they are being irritated by too much UVA light? I have a Reptisun 10 about 10 inches off the substrate and a 75 watt ZooMed Halogen basking light, which also gives off UVA, at about the same distance.

--Mr. Puff

 

[GBtortoises]

There have been recent cases reported of retina damage caused in tortoises and some lizards by very intense UVA bulbs such as the Reptisun 10 and others. At 10" from the substrate I would say that it is definitely way too much, especially for northern Testudo species. Even with a less intense bulb it should be a bit farther from the substrate. There is also no need to have both lights producing UV rays. If you have the Halogen there is no reason to have the other. If you have just a UV flourescent, you should also have a basking light. Depending upon how close the 75w bulb is to the substrate it may also be too hot for the tortoise underneath the bulb. A 75w halogen bulb produces alot of heat! I use standard 40w incandescent bulbs for basking, mounted about 12" from the substrate and they produce a temperature of around 100 degree directly under the center of the light beam at the substrate. I use flat stones to absorb the heat right under the light. You may need to use a higher wattage than I do based on the ambient temperature of the room that your tortoise is housed in. The temperatures in my room during the daytime averages 75-78 degrees.

 

[mctlong]

I've been having similar problems with my hatchling and I was also also using the Reptisun 10.0 until I saw post here http://tortoiseforum.org/thread-10023.html
this morning warning about the blindness issues.

Here's the link describing the snow blindness caused by some of the compact UVA/UVB bulbs. Its scary stuff.

http://www.uvguide.co.uk/phototherapyphosphor-summary.htm

 

[bettinge]

Personally I feel the Reptisun 10.0 bulb is best used for an arborial reptile like the chameleons! The 10.0 bulb is effective up to 20 inches! For reptiles like torts, I prefer the MVB or maybe the ReptiSun 5.0 bulb.
I would suggest not using the 10.0 bulb for a while and see if things get better. If they do get better, try to put the bulb 18-20 inches away!

 

[Mr.Puff]

OK, I swapped out my Reptisun 10 for a Zilla Desert 50, which increases the distance to about 14". I also changed out the 75 watt halogen for a 40 watt incandescent. His hot spot is still 95 degrees (I use a rheostat), but no extra UVA rays are there to burn him.