Catch light or catchlight is a light source that causes a specular highlight in a subject's eye in an image. They are also referred to as eye lights or Obies, the latter a reference to Merle Oberon, who was frequently lit using this technique. A catch light may be an artifact of the lighting method, or have been purposely engineered to add a glint or "spark" to a subject's eye during photography. This technique is useful in both still and motion picture photography. Adding a catch light can help draw attention to the subject's eyes, which may otherwise get lost among other elements in the scene.
A catch light is not the same as the red-eye effect; in general, red-eye is an undesired effect (caused by the reflection of light from the retina inside the back of the eyeball), while catch lights are often aesthetically desirable, and produced by light reflecting from the cornea. Especially in portraiture, eyes without catch lights are often said to appear dull or lifeless. Lighting is often arranged in studio portraits specifically to create attractive catch lights.