/of thal"meuh skohp', op-/, n.an instrument for viewing the interior of the eye or examining the retina.[1855-60; OPHTHALMO- + -SCOPE]
* * *instrument for inspecting the interior of the eye, invented in 1850 by the German physiologist Hermann von Helmholtz (Helmholtz, Hermann von). The ophthalmoscope became a model for later forms of endoscopy. The device consists of a strong light that can be directed into the eye by a small mirror or prism. The light reflects off the retina and back through a small hole in the ophthalmoscope, through which the examiner sees a nonstereoscopic magnified image of the structures at the back of the eye, including the optic disk, retina, retinal blood vessels, macula, and choroid. The ophthalmoscope is particularly useful as a screening tool for various ocular diseases, such as diabetic retinopathy.
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