In photography, "catch lights" refer to the specular highlights that appear in a subject's eyes when light sources reflect off them. These highlights can be seen as small, bright spots or reflections that bring a sense of life and dimension to the subject's eyes, making them appear more vibrant and engaging. 

Catch lights are an important element in portrait photography because they add a sense of depth and realism to the subject's eyes, making them more engaging and captivating to the viewer. They are created by positioning light sources such as studio lights, natural light or reflectors in such a way that they reflect off the surface of the subject's eyes. 

The size and shape of the catch lights can also vary depending on the size, shape, and position of the light source relative to the subject's eyes. Photographers may use catch lights intentionally to create a specific mood or effect, or they may simply seek to capture natural catch lights that occur in everyday lighting situations.

Judges usually look for catch lights so consider editing them in if they are missing.