Which phenomenon describes the fading of peripheral images when the eye is fixated on a central object?

• A. Mach Bands
• B. Afterimage
• C. Persistence of Vision
• D. Troxler Effect

Answer: (D)

Fading of peripheral details when you fixate on a central target is called the Troxler effect. When the eye holds a steady gaze, neurons in the peripheral retina adapt to the constant, unchanging stimulation. The central area continues to be stimulated by the fixation point, so the peripheral image details fall from conscious perception while the center remains visible. This is different from an afterimage (which persists after you move away from a bright stimulus), persistence of vision (brief retention of an image after exposure ends, like in film), or Mach bands (illusory light/dark edges at contrast boundaries). The Troxler effect specifically describes the fixation-related fading of peripheral images.