photo-, phot-, -photic +

1. A pathological effect caused by light.
2. The influence of light upon organisms.
3. Any abnormal change in the skin induced by light.

The ability to perceive light.

1. The length of a day.
2. The amount of time that an organism is exposed to daylight.

1. A property of living organisms wherein biochemical, physiological, and behavioral changes occur in response to systematic variations in light and darkness, as with the seasons or day and night.
2. Any of various behavioral and physiological changes in an organism in response to the amount of daylight to which the organism is exposed; for example, the relative length of day and night on a seasonal or daily basis.

The study of the effects of light and other radiations on drugs and on their pharmacological action.

A process in which peripheral blood is exposed in an extracorporeal flow system to photoactivated 8-methoxypsoralen (methoxsalen) and ultraviolet light; a procedure known as puva therapy.

Photopheresis is at present a standard therapy for advanced cutaneous T-cell lymphoma. It shows promise in the treatment of autoimmune diseases.

1. In biology, thriving in conditions where there is full light.
2. Loving light, tending towards a lighted region; thriving best in abundant light.

1. Thriving in light; said of organisms.
2. Thriving in intense light.

1. In biology, thriving in light.
2. Loving light; fond of light; attracted to light.

1. An excessive fear of and avoidance of light; painful sensitivity to light, especially visually.
2. In botany, the tendency to thrive in reduced light, as with certain plants.
3. Intolerant of, or avoiding, conditions of full light.

In biology, a response of an organism to a temporal change in light intensity.

It is positive when stimulated by a decrease in light intensity and negative when stimulated by an increase.

An instrument for producing sound by the action of light waves.

A luminous light organ on many deep sea and some nocturnal fish, squids, and shrimps.

The process in photosynthesis that converts light energy to stored energy in plants and bacteria.

Ophthalmia caused by intense light, such as an electric light, rays from a welding arc, or reflection from snow (ophthalmia nivialis).