An afterimage or ghost image or image burn-in is an optical illusion that refers to an image continuing to appear in one's vision after the exposure to the original image has ceased. One of the most common afterimages is the bright glow that seems to float before one's eyes after looking into a light source for a few seconds

Natural Sciences & Mathematics » Astronomy » Satellites The look angle of the earth station in degrees above the horizon.

a plastic lens implanted surgically to replace the eye's natural crystalline lens, usually because the natural lens has developed a cataract.