I've read more than I care to about bulbs and UVB and this rate and that measure. This is for information only to people who may need it. I just recently adopted a baby beardie. It started acting 'funny' and worried my wife (she loves this thing already!). She googled 'beardie won't open eyes' and the odyssey began. Elliot's symptoms fit EXACTLY those of photo-kerato-conjunctivitis although I am not a vet. We've used 2 bulbs all day and none at night since we brought 'him' (not sexed yet) home. They are the Exo Terra Repti Glo 10.0 compact and the Zilla Incandescent White Light Spot 50W. Also, my Repti Glo compact 10.0 has the box with the charts on it which I read in one of the threads here means it's one of the newer, better bulbs since the recalls, replacements, etc.