Although Rosenthal's original experiments used full-spectrum fluorescent tubes, his later research showed that light from incandescent and halogen bulbs was just as effective. No one bulb is definitely better than another. Even intensity may not matter. Amount of exposure time is also unclear. A typical treatment strategy begins with having the patient set up a light box on a table to sit directly in front of while eating breakfast or reading the newspaper.
Exercise is also a critical element of treatment.
Dr. Rosenthal suggests taking a quick walk during lunch breaks. Even on overcast days, the sunlight filtering through the clouds is beneficial. In the evenings the patient can have another session in front of the light box, perhaps while eating dinner. It's not necessary, or even recommended, to stare into the light. The entire retina responds to light, so it's possible to get the full benefit of light therapy while reading, talking on the phone or even watching television.