Ophthalmoscopy

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Ophthalmoscope
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Ophthalmoscopy
Ophthalmoscopic exam: the medical provider would next move in and observe with the ophthalmoscope from a distance of one to several cm.
MeSHD009887

Ophthalmoscopy, also called funduscopy, is a test that allows a health professional to see inside the

vitreous humor.[citation needed
]

The pupil is a hole through which the eye's interior will be viewed. Opening the pupil wider (dilating it) is a simple and effective way to better see the structures behind it. Therefore, dilation of the pupil (mydriasis) is often accomplished with medicated eye drops before funduscopy. However, although dilated fundus examination is ideal, undilated examination is more convenient and is also helpful (albeit not as comprehensive), and it is the most common type in primary care.

An alternative or complement to ophthalmoscopy is to perform a fundus photography, where the image can be analysed later by a professional.

Types

Ophthalmoscope (left) and otoscope combination by Welch Allyn
macula is in the center of the image, and the optic disc
is located towards the nose. Both optic discs have some pigmentation at the perimeter of the lateral side, which is considered non-pathological. The left image (right eye) shows lighter areas close to larger vessels, which has been regarded as a normal finding in younger people.

It is of two major types:

  • Direct ophthalmoscopy one that produces an upright, or unreversed, image of approximately 15 times magnification.
  • Indirect ophthalmoscopy one that produces an inverted, or reversed, image of 2 to 5 times magnification.
Features Direct ophthalmoscopy Indirect ophthalmoscopy
Condensing lens Not Required Required
Examination distance As close to patient's eye as possible At an arm's length
Image Virtual, erect Real, inverted
Illumination Not as bright; not useful in hazy media Bright; useful for hazy media
Area of field in focus About 2-8 disc diameters About 8 disc diameters
Stereopsis Absent Present
Accessible fundus view Slightly beyond equator[further explanation needed] Up to Ora serrata i.e. peripheral retina
Examination through hazy media Difficult to not possible Possible

Each type of ophthalmoscopy has a special type of ophthalmoscope:

Medical uses

Ophthalmoscopy is done as part of a routine physical or complete eye examination, mainly done by

cerebrovascular accidents (strokes).[citation needed
]

Dilation of the pupil

Main article: Dilated fundus examination

To allow for better inspection through the

mydriatic agent, for instance tropicamide, or simply reducing the brightness of the ophthalmoscope, which may slightly increase natural mydriasis, allowing a better view of the posterior eye. It is primarily considered ophthalmologist or optometrist equipment, but is used by other specialists as well, including neurology and internal medicine. Recent developments like scanning laser ophthalmoscopy can make good quality images through pupils as small as 2 millimeters, so dilating pupils is no longer needed with these devices.[citation needed
]

History

William Cumming in 1846 at the Royal London Ophthalmic Hospital (later Moorfields Eye Hospital), of his pioneering work wrote "every eye could be made luminous if the axis from a source of illumination directed towards a person's eye and the line of vision of the observer were coincident".[2]

Although some credit the invention of the ophthalmoscope to Charles Babbage in 1847, it was not until it was independently reinvented by Hermann von Helmholtz in 1851 that its usefulness was recognized - it was to revolutionize ophthalmology.[3]

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. Austin Barnett 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.[citation needed]

In 1915, Francis A. Welch and William Noah Allyn invented the world's first hand-held direct illuminating ophthalmoscope,[4] 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 Welch Allyn started as a result of this invention. In the 1970s a new ophthalmoloscope was developed with a larger primary lens allowing a 5x larger field-of-view, called the "Panoptic" or "pan ophthalmoscope".[5]

Etymology and pronunciation

The word ophthalmoscopy (

usage note.[10]

See also

References

  1. ^ a b "Ophthalmoscopy | Michigan Medicine". Healthwise. Retrieved 10 July 2019.
  2. ^ "Ophthalmoscopes Part 1". Retrieved 2013-01-25.
  3. ^ "Principles of Ophthalmoscopy". lifehugger.com. Retrieved 2009-05-24.
  4. ^ Hoovers Citation
  5. ^ Allyn, Welch. "PanOptic Ophthalmoscope". www.welchallyn.com. Retrieved 2019-01-29.
  6. ^ Merriam-Webster, Merriam-Webster's Medical Dictionary, Merriam-Webster.
  7. ^ Merriam-Webster, Merriam-Webster's Unabridged Dictionary, Merriam-Webster.
  8. ^ Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.
  9. ^ Houghton Mifflin Harcourt, The American Heritage Dictionary of the English Language, Houghton Mifflin Harcourt, archived from the original on 2015-09-25, retrieved 2015-10-21.
  10. ^ Wolters Kluwer, Stedman's Medical Dictionary, Wolters Kluwer.

External links

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