ophthalmoscope

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ophthalmoscope

(ŏfthăl`məskōp'), instrument used for examining the inner structure of the eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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. The device was invented by the German physiologist H. L. F. von Helmholtz in 1851. His model consisted of three plates of glass pressed together and mounted on a handle at a 45° angle. A light was placed beside the subject whose eyes were to be examined. Some light passed through the plates, but some was reflected back into the eye. The form of the instrument now in general use consists of a concave mirror and a battery-powered light source within a tubular handle. Sighting is through a single or binocular eyepiece. The ophthalmoscope is equipped with a rotating disc of lenses to permit observation of the eye at varying depths and magnifications. Examination of the eye may be enhanced by administering drugs to dilate the pupil.

ophthalmoscope

[äf′thal·mə‚skōp]
(optics)
An instrument, consisting essentially of a concave mirror with a hole in it and fitted with lenses of different powers, for examining the interior of the eye through the pupil.

ophthalmoscope

an instrument for examining the interior of the eye
References in periodicals archive ?
With a direct ophthalmoscope a clear view of the optic disc, blood vessels and the nerve fiber layer is obtained.
Use a pen-torch or direct ophthalmoscope as the light source and illuminate the pupil from below (or temporally) at a distance of 5-10cm.
On 1st and 2nd post-operative days all patients were examined under slit lamp, fundus was examined with +90D lens and by direct ophthalmoscope, pinhole visual acuity was recorded and follow up examination was done at second week, fourth and sixth week in all patients.
Examination included best corrected visual acuity and undilated fundoscopy using a direct ophthalmoscope.
Gone are the days when practitioners were armed with nothing more that a direct ophthalmoscope, and a Bjerrum screen; those entering the profession today have an abundance of technology at their disposal, including video slit lamps, automated visual fields, fundus cameras, OCT, with the list lengthening year-on-year.
With normal direct ophthalmoscope we can see 10 to 30 degrees of retina only and it also needs training.

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