A fog lamp for use in an automobile includes a light source, a reflector, and a condenser lens. The front surface of the condenser lens includes an emission region and two diffusion regions. The diffusion regions have a surface treatment that diffuses transmitted light, such as knurling, frosting, texturing, or pillowing. Light emitted by the light source is directed by the reflector through the condenser lens and exits the condenser lens through the emission region. Light that enters the condenser lens through one of the diffusion regions from outside of the lamp, such as solar light, is diffused and reduced in intensity. The diffusion regions may be positioned relative to a back surface of the lens to cause the diffused light to be reflected due to total internal reflection. The diffused light may exit the lens through the other diffusion region and become further diffused and reduced in intensity.