jump

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Related to jump the gun: keep one's nose to the grindstone

jump

The displacement of the image of an object occurring when viewing across the borderline between two portions of different power in a bifocal or trifocal lens. The jump is eliminated by placing the optical centres on the dividing line; the lens is then called a no jump bifocal (e.g. a monocentric bifocal with a straight dividing line) (Fig. J1). Syn. image jump; prismatic jump. See monocentric.
Fig. J1 Image jump upward caused by the segment of a bifocal lens, as the direction of gaze is lowered across the dividing lineenlarge picture
Fig. J1 Image jump upward caused by the segment of a bifocal lens, as the direction of gaze is lowered across the dividing line
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
Before they jump the gun and blame Israel, let us see if the Arab League can play the Good Samaritan or will it be that the Palestinian people are still considered the lepers of the Arab world and the hypocritical Arabs wringing their hands at the plight of their neighbours will be shown for what they really are?
How the article is worded seems mean spirited and a bit hateful to jump the gun or in this case to jump the string to tell readers to bad mouth a bow manufacturers string without first giving them an opportunity to make it right or addressing it in a more direct manner.
Neil Willis, of Cramlington, wrote: "To jump the gun means to start something before the proper time, the origin of this phrase appears to relate to athletes starting a race before the starting gun has gone off."
Although most individuals in dementia's advanced stages do need someone to assist them with medical decisions, many professionals all too frequently jump the gun on individuals who have dementia in the early stages.