OPHTHALMOSCOPE

instrument for inspecting the interior of the eye, invented in 1851 by the German physiologist Hermann von Helmholtz. The device consists of a strong light that can be directed into the eye by a small mirror. The light reflects off the retina and back through a small hole in the ophthalmoscope, through which the examiner sees a magnified image of the structures at the back of the eye, including the optic disk, retina, blood vessels, macula, and choroid.