Phototherapy is a type of medical treatment that involves exposure to fluorescent light bulbs or other sources of light like halogen lights, sunlight, and light emitting diodes (LEDs) to treat certain medical conditions.There are different types of phototherapy and the kind, as well as the technique used by your doctor, will depend on the condition you have that is being treated.Phototherapy has been used to treat medical conditions for as far back as 3,500 years ago when ancient the Egyptians and Indians used sunlight to treat skin conditions like vitiligo.Modern phototherapy, using artificial light sources, began with Niels Ryberg Finsen. Widely regarded as the founder of modern phototherapy, he treated a skin condition called lupus vulgaris with sunlight and ultraviolet radiation.1 From then on, usage of phototherapy in medical fields grew, techniques were refined and developed, and it eventually gained widespread acceptance.