[Normal doses of visible light can cause mutations in skin]

Therapeutic and undesired effects of long-wave (UVA1) (340-400 nm) and visible light were studied. Mutagenicity were investigated after repeated doses encountered in normal situations in the sun. Laser treatment of naevus flammeus was studied with a new 600 nm laser. Also, the effect of photodynamic therapy on cutaneous lymphomas was reported. Both UVA1 and visible light can induce mutations in normal skin after repeated doses. The findings indicate that clothing, not sunscreens, should form the basis of sun protection. In selected cases, the new 600 nm laser may be advantageous in the treatment of naevus flammeus. Localized cutaneous lymphoma may be effectively treated with photodynamic therapy.