Keep this page still. In a moment, something on it may vanish. The surprise is in your eye.
Try it yourself
Use the cross and dot below. Close your left eye and look steadily at the cross with your right eye. Start roughly an arm’s length away, then slowly change your distance from the screen. Keep watching the cross rather than chasing the dot. At a particular distance, the dot can disappear; move again and it returns. [1]
If it does not work immediately, adjust your distance or hold the screen at eye level. Screen size and positioning affect the demonstration.
Where did it go?
There is a small area of your retina where the optic nerve exits and no light receptors are present. When the dot’s image lands there, that eye cannot detect it. [1]
Yet you usually experience a continuous view. Information from the surrounding scene helps your visual system fill the gap; with both eyes open, their views also overlap. What feels like an uninterrupted picture is already being assembled for you. [1]
What to keep in mind
This is an educational demonstration, not a vision test. It illustrates a normal feature of the eye.
Sources & context
Numbered references link the explanation to its sources. Hypothetical examples and visual metaphors are labelled in the text. Checked 2 October 2026.
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