n. a device used to assess the refractive state of the eye. It projects a beam of light into the eye; by determining the direction in which the light moves when the retinoscope is moved, the clinician can detect myopia, hyperopia, and astigmatism. Lenses of various powers can be placed between the retinoscope and the eye to determine the correction that provides the best refraction for the patient. Compare ophthalmoscope.