chromatic aberration
An effect where the edges of an image have a colored, blurry halo or fringe. The RGB color channels appear noticeably offset from one another.
In photography, chromatic aberration is caused by a defect of the camera lens. The lens refracts light of different wavelengths (colors) slightly differently (technically speaking, the index of refraction of a lens material varies depending on the wavelength), causing the colors to become out of focus.
In digital art, chromatic aberration is used to simulate a photographic look or for artistic effect. In small amounts it can increase realism; in greater amounts it can create a sense of motion (similar to motion blur), convey a chaotic environment, or indicate anxiety, paranoia, or mental derangement. In excessive amounts it can induce eyestrain.