photorefraction


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photorefraction 

A family of photographic techniques that provide a rapid, objective method of measuring the refractive error and accommodative response of the eye. Light emitted from a small flash source placed close to the camera lens is reflected from the eye and returned to the camera. Three methods have been developed: orthogonal, isotropic and eccentric (also called photoretinoscopy). The optical design of each method results in a specific photographic pattern, which varies with the degree to which the eye is defocused with respect to the plane of the camera. Photorefractive methods are not as accurate as retinoscopy but as they are entirely objective, much quicker and do not require prolonged fixation on the part of the patient, they are highly suited for testing infants and young children. See optometer; refractive error; retinoscope.
References in periodicals archive ?
Since streak retinoscopy is a time-consuming technique for this kind of animals, alternative objective techniques such infrared photorefraction might be more appropriate [4, 24] in future experiments.
However, the phenomenon of a photorefraction is an essential limiting factor (Galutskiy, Vatlina, and Stroganova, 2009; Kolker, Dmitriev, Gorelick, Wong, and Zondi, 2009.), when using PPLN as a nonlinear and optical element in processes of obtaining radiation of the second harmonica of powerful continuous lasers for creation of a bright contrast picture in such appendices as projective television and others the device multimedia.
Investigations in the 1980s of various species by means of retinoscopy and photorefraction (Martin and Young) suggested penguin corneas are relatively flat with a refractive power of about 29D which is neutralised under water.