Eye refraction examined by aid of speckle pattern produced by coherent light

After a brief outline of the formation and properties of laser-produced speckles, the paper describes a method of measuring the eye refraction based on the observation that the speckles from an illuminated surface appear to move when the surface and the eye have an angular movement relative to one another. Movements of the speckle pattern in the same or the opposite direction as the apparative movement indicate over- or undercorrection. The results of a simple mathematical theory of the phenomenon, including sensitivity calculations, is given. A test apparatus is described, as well as findings when this is used at a number of subjects.