- Ophthalmoscope
The ophthalmoscope (or funduscope) is an instrument used to examine the
eye . Its use is crucial in determining the health of theretina and thevitreous humor .In patients with
headache s, the finding of swollenoptic disc s, orpapilledema , on ophthalmoscopy is a key sign, as this indicates raisedintracranial pressure (ICP) which could be due tohydrocephalus ,benign intracranial hypertension (aka pseudotumor cerebri) orbrain tumor , amongst other conditions. Cupped optic discs are seen inglaucoma .In patients with
diabetes mellitus , regular ophthalmoscopic eye examinations (once every 6 months to 1 year) is mandatory to screen fordiabetic retinopathy as visual loss due to diabetes can be prevented by retinal laser treatment if retinopathy is spotted early.In
arterial hypertension , hypertensive changes of the retina closely mimic those in the brain, and may predictcerebrovascular accident s (strokes).Numerous companies manufacture direct ophthalmoscopes, including Welch Allyn, Heine, Riester and Keeler. Ophthalmoscopes are often sold with
otoscope s as a diagnostic set.History
Although originally invented by
Charles Babbage in 1847, it was not until it was independently reinvented byHermann von Helmholtz in 1851 that its usefulness was recognized.While training in France,
Andreas Anagnostakis , MD, an ophthalmologist from Greece, came up with the idea of making the instrument hand-held by adding a concave mirror. Liebreich created a model for Anagnostakis, which he used in his practice and subsequently when presented at the first Ophthalmological Conference in Brussels in 1857, the instrument became very popular among ophthalmologists.In 1915, Willam Noah Allyn and Frederick Welch invented the world's first hand-held direct illuminating ophthalmoscope [ [http://www.hoovers.com/welch-allyn,-inc./--ID__54678--/free-co-factsheet.xhtml Hoovers Citation] ] , precursor to the device now used by clinicians around the world. This refinement and updating of von Helmholtz's invention enabled ophthalmoscopy to become one of the most ubiquitous medical screening techniques in the world today. The company started as a result of this invention is
Welch Allyn .Types
There are two major types of ophtalmoscopes, direct and indirect.
Direct ophthalmoscope
It is an instrument about the size of a small flashlight (torch) with several lenses that can magnify up to about 15 times. This type of ophthalmoscope is most commonly used during a routine physical examination [http://www.healthbanks.com/PatientPortal/Public/LinkPublic.do?ArticleID=HW5hw5223 healthbanks.com] ]
Indirect ophthalmoscope
An indirect ophthalmoscope constitutes a light attached to a headband, in addition to a small handheld lens. It provides a wider view of the inside of the eye. Furthermore, it allows a better view of the
fundus of the eye , even if the lens is clouded bycataract s .An indirect ophthalmoscope can be either monocular or binocular.
ee also
*
Charles Schepens
*Retinoscope
*Scanning laser ophthalmoscopy References
External links
* [http://careerfocus.bmjjournals.com/cgi/content/full/329/7461/56 Overview at bmjjournals.com]
* [http://www.sciencedaily.com/releases/2007/03/070305140957.htm A new digital hand held ophthalmoscope] - sciencedaily.com -
* [http://www.nlm.nih.gov/medlineplus/ency/article/003881.htm Medlineplus] about different types of ophtalmoscopy
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