View source for Ophthalmoscopy

{{Short description|Part of an eye examination}}{{More citations needed|date=June 2024}}{{Infobox interventions |
  Name        = Ophthalmoscopy |
  Image       = Ophthalmoscopy.JPG |
  Caption     = Ophthalmoscopic exam: the medical provider would next move in and observe with the ophthalmoscope from a distance of one to several cm. |
  ICD10       = |
  ICD9        = |
  MeshID      = D009887 |
  OPS301      = |
  OtherCodes  = |
  HCPCSlevel2 =
}}

'''Ophthalmoscopy''', (from [[Ancient Greek]] ὀφθαλμός (''ophthalmós''), meaning "eye", and σκοπέω (''skopéō''), meaning "to look") also called '''funduscopy'''<!-- Do not change spelling before reading section [[#Etymology and pronunciation]] -->, is a test that allows a health professional to see inside the [[Fundus (eye)|fundus of the eye]] and other structures using an '''ophthalmoscope''' (or '''funduscope'''). It is done as part of an [[eye examination]] and may be done as part of a routine [[physical examination]]. It is crucial in determining the health of the [[retina]], [[optic disc]], and [[vitreous humor]].{{cn|date=June 2022}}

The [[pupil]] is a hole through which the eye's interior can be viewed. For better viewing, the pupil can be opened wider (dilated; [[mydriasis]]) before ophthalmoscopy using medicated [[eye drop]]s ([[dilated fundus examination]]). However, undilated examination is more convenient (albeit not as comprehensive), and 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==
[[Image:Ophthalmoscope Otoscope08.JPG|thumb|Ophthalmoscope (left) and [[otoscope]] combination by Welch Allyn]]
{{multiple image
   | direction = horizontal
   | width     = 150
   | footer    = [[Fundus photographs]] of the left eye (left image) and right eye (right image). Each [[Fundus (eye)|fundus]] has no sign of disease or pathology. The gaze is into the camera, so in each picture the [[Macula of retina|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 right image (right eye) shows lighter areas close to larger vessels, which has been regarded as a normal finding in younger people.
   | image1    = Fundus photograph of normal left eye.jpg
   | alt1      =
   | caption1  =
   | image2    = Fundus photograph of normal right eye.jpg
   | alt2      =
   | caption2  = }}
There are two major types of ophthalmoscopy:
* '''direct ophthalmoscopy''', which produces an upright (unreversed) image of approximately 15× magnification
* '''indirect ophthalmoscopy''', which produces an inverted (reversed) image of 2–5× magnification

{| class="wikitable" border="1"
! 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 image|Virtual]], [[Erect image|erect]]
| [[Real image|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{{explain|date=July 2019}}
| Up to [[ora serrata]], i.e. peripheral [[retina]]
|-
| ''Examination through hazy media''
| Difficult to impossible
| Possible
|}

<!-- * '''[[Slit lamp|Slit-lamp]] ophthalmoscopy''' -->
Each type of ophthalmoscopy has a special type of ophthalmoscope:
* Direct ophthalmoscopy uses the direct ophthalmoscope, an instrument the size of a small flashlight with several lenses that can magnify up to about 15 times.<ref name=ophthalmoscopy>{{cite web |title=Ophthalmoscopy {{!}} Michigan Medicine |url=https://www.uofmhealth.org/health-library/hw5223 |publisher=Healthwise |access-date=10 July 2019}}</ref> This type of ophthalmoscope is most commonly used during a routine physical examination. The pan-ophthalmoscope has a larger primary lens with a variable focusing, allowing for a wider field-of-view.
* Indirect ophthalmoscopy uses the indirect ophthalmoscope, an instrument that has 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 (eye)|fundus of the eye]], even if the lens is clouded by [[cataract]]s.<ref name=ophthalmoscopy/> An indirect ophthalmoscope can be either monocular or binocular. It is used for peripheral viewing of the retina.

==Medical uses==

Ophthalmoscopy is done as part of a routine physical or complete eye examination, mainly by [[optometrists]] and [[ophthalmologists]]. It is used to detect and evaluate symptoms of various [[retinal vascular diseases]] and eye diseases.

In patients with [[headache]]s, the finding of swollen [[optic disc]]s ([[papilledema]]) on ophthalmoscopy is a key sign indicating raised [[intracranial pressure]], which may be due to conditions such as [[hydrocephalus]], [[benign intracranial hypertension]] (pseudotumor cerebri), and [[brain tumor|brain tumors]]. In glaucoma, cupped optic discs are seen. In patients with [[diabetes mellitus]], regular ophthalmoscopic eye examinations (once every 6 months to 1 year) are important to screen for [[diabetic retinopathy]], as visual loss due to diabetes can be prevented by [[Laser coagulation|retinal laser treatment]] if retinopathy is spotted early. In [[arterial hypertension]], hypertensive changes of the retina closely mimic those in the brain and may predict [[cerebrovascular accident]]s (strokes).{{citation needed|date=November 2019}}

==Dilating the pupil==
{{Main|Dilated fundus examination}}

During ophthalmoscopy, the pupil constricts due to light from the ophthalmoscope. To allow for better inspection of the posterior eye through the pupil, it is often desirable to dilate (enlarge) the pupil by applying a [[Mydriasis#Drugs|mydriatic agent]] (e.g. [[tropicamide]]), or by reducing the ophthalmoscope's brightness, which may slightly increase natural [[mydriasis]].{{cn|date=December 2021}}

Mydriatic agents are primarily considered ophthalmologist or optometrist equipment, but is used by other specialists as well, including neurologists and internists. Recent developments like [[scanning laser ophthalmoscopy]] can make good quality images through pupils as small as {{Convert|2|mm|in|abbr=on}}, so dilating the pupil is not necessary with these methods.{{cn|date=December 2021}}

==History==

=== Early models ===
The first instrument for looking into the eye was first invented in 1847 by British inventor [[Charles Babbage]]. However, he was unable to obtain an image with the instrument when showing it to ophthalmologist [[Thomas Wharton Jones]], and thus became discouraged to proceed further. The instrument is described by Jones as follows:<ref name="Observations of the Fundus" />
{{Quote|text=It consisted of a bit of plain mirror, with the silvering scraped off at two or three small spots in the middle, fixed within a tube at such an angle that the rays of light falling on it through an opening in the side of the tube, were reflected into the eye to be observed, and to which the one end of the tube was directed. The observer looked through the clear spots of the mirror from the other end.<ref name="Observations of the Fundus" />|author=Thomas Wharton Jones|title="Report on the Ophthalmoscope", Chronicle of Medical Science (October 1854)}}
Later in 1851, German physiologist [[Hermann von Helmholtz]] invented the ophthalmoscope again independently. At that time, Helmholtz was a young [[physiology]] professor and wanted to demonstrate to his students why the [[pupil]] was sometimes black and sometimes light. He wrote about his ophthalmoscope in detail and demonstrated that it required three essential components (which remain true today):<ref name="Observations of the Fundus" />

* a source of illumination (Helmholtz used a candle)
* a method of reflecting the light into the eye
* an optical method for correcting an unsharp image of the [[Fundus (eye)|fundus]]

Helmholtz called his instrument an {{Lang|de|Augenspiegel}} ('eye mirror'). The name "ophthalmoscope" only came into common use in 1854, three years after the instrument's invention.<ref name="Observations of the Fundus" />

=== Later improvements ===
Helmholtz's first ophthalmoscope could not correct for [[Refractive error|refractive errors]] in the patient and/or the observer. This limitation was solved in 1852 by Helmholtz' machinist, Egbert Rekoss, who added two rotatable discs that each contained a few lenses. These wheels of lenses were superior to other early opthalmoscopes which used separate individual lenses that were inconvenient to change. The discs are known as the "Rekoss Disc" and continue to be used on most hand-held ophthalmoscopes today.<ref>{{Cite web |last=Keeler |first=Richard |title=Ophthalmoscopes Part 2 |url=http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ophthalmoscopes2.cfm |url-status=dead |archive-url=https://web.archive.org/web/20120110092426/http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ophthalmoscopes2.cfm |archive-date=2012-01-10 |access-date=2024-06-18 |website=[[College of Optometrists]]}}</ref>

Observing the eye's interior required alignment of the observer's vision and the light source. This was discovered by William Cumming, a young ophthalmologist at the [[Royal London Ophthalmic Hospital]], who wrote that "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". To eliminate this variable, some (including [[Lionel Smith Beale|Lionel Beale]]) created ophthalmoscopes with an attached light source.<ref name="Observations of the Fundus">{{cite web |last=Keeler |first=Richard |title=Ophthalmoscopes Part 1 |url=http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ |url-status=dead |archive-url=https://web.archive.org/web/20120110092541/http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ |archive-date=2012-01-10 |access-date=2013-01-25 |website=[[College of Optometrists]]}}</ref>

While training in France, Greek ophthalmologist [[Andreas Anagnostakis]] 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 presented at the first Ophthalmological Conference in [[Brussels]] in 1857, which made the instrument very popular among ophthalmologists.{{cn|date=December 2021}}

The invention of the [[incandescent light bulb]] further enabled the ophthalmoscope to be self-luminous instead of relying on an external and remote source of illumination.<ref name=":0">{{Cite web |last=Keeler |first=Richard |title=Ophthalmoscopes Part 3 |url=http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ophthalmoscopes3.cfm |url-status=dead |archive-url=https://web.archive.org/web/20120109043258/http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ophthalmoscopes3.cfm |archive-date=2012-01-09 |access-date=2024-06-18 |website=[[College of Optometrists]]}} [http://www.college-optometrists.org/en/knowledge-centre/museyeum/online_exhibitions/optical_instruments/ophthalmoscopes/ophthalmoscopes3.cfm Alt URL]</ref> The first ophthalmoscope to have an installed light bulb was created by William Dennet, who presented his invention to the [[American Ophthalmological Society]] in 1885, though it was unreliable as the light bulb's life was short and unpredictable.<ref name="Observations of the Fundus" />

The ophthalmoscope was further improved in 1915 by G.S. Crampton, who added a battery to the handle for powering the light source, thus making the instrument portable.<ref name=":0" />

In 1915, Francis A. Welch and William Noah Allyn invented the world's first hand-held direct-illuminating ophthalmoscope. The company [[Welch Allyn]] started as a result of this invention.<ref>{{Cite web |title=Welch Allyn, Inc. |url=http://www.hoovers.com/welch-allyn,-inc./--ID__54678--/free-co-factsheet.xhtml |url-status=dead |archive-url=https://web.archive.org/web/20070929141123/http://www.hoovers.com/welch-allyn,-inc./--ID__54678--/free-co-factsheet.xhtml |archive-date=2007-09-29 |website=[[D&B Hoovers|Hoovers]]}}</ref> In the 2000s, the company developed a new design of ophthalmoscope called the "Panoptic". The instrument produced an image with a field-of-view five times larger than conventional direct ophthalmoscopes.<ref name=":0" /><ref>{{Cite web |last= |first= |title=PanOptic Ophthalmoscope |url=https://www.welchallyn.com/en/products/categories/physical-exam/eye-exam/ophthalmoscopes--wide-view-direct/panoptic_ophthalmoscope.html |url-status=dead |archive-url=https://web.archive.org/web/20190116011124/https://www.welchallyn.com/en/products/categories/physical-exam/eye-exam/ophthalmoscopes--wide-view-direct/panoptic_ophthalmoscope.html |archive-date=2019-01-16 |access-date=2019-01-29 |website=[[Welch Allyn]]}}</ref>

==Etymology and pronunciation==
The word ''ophthalmoscopy'' ({{IPAc-en|ˌ|ɒ|f|θ|æ|l|ˈ|m|ɒ|s|k|ə|p|i}}) uses [[classical compound|combining forms]] of ''[[wikt:ophthalmo-#Prefix|ophthalmo-]]'' + ''[[wikt:-scopy#Suffix|-scopy]]'', yielding "viewing the eye". The word ''funduscopy'' ({{IPAc-en|f|ʌ|n|ˈ|d|ʌ|s|k|ə|p|i}}) derives from ''[[wikt:fundus|fundus]]'' + ''[[wikt:-scopy#Suffix|-scopy]]'', yielding "viewing the far inside". The idea that ''fundus'' can and should correspond to a combining form ''fundo-'' drives the formation of an alternate form, ''fundoscopy'' (''fundo-'' + ''-scopy''), which is the subject of a [[linguistic description|descriptive]]-versus-[[linguistic prescription|prescriptive]] difference in acceptance. Some dictionaries enter the ''fundo-'' form as a second-listed variant,<ref name="MW_Medical">{{Cite Merriam-Webster|funduscopy|medical}}</ref> but others do not enter it at all,<ref name="Dorlands">{{Citation |title=funduscope |website=Dorland's Illustrated Medical Dictionary |publisher=Elsevier |url=https://www.dorlandsonline.com/dorland/definition?id=19420 }}</ref> and one prescribes its avoidance with a [[usage]] note.<ref name="Stedmans">{{Citation  |title=Stedman's Medical Dictionary |publisher=Wolters Kluwer |url=http://stedmansonline.com/ }}</ref>

==See also==
* [[Charles Schepens]]
* [[Retinoscope]]
* [[Scanning laser ophthalmoscopy]]

==References==
{{reflist}}

==External links==
* [https://www.medlineplus.gov/ency/article/003881.htm Ophthalmoscopy on Medlineplus]
* [http://www.webmd.com/eye-health/ophthalmoscopy Ophthalmoscopy on WebMD]
* [https://web.archive.org/web/20080420061116/http://careerfocus.bmjjournals.com/cgi/content/full/329/7461/56 Overview at bmjjournals.com]
* [https://www.medlineplus.gov/ency/article/003881.htm Medlineplus] about different types of ophthalmoscopy

{{Health care}}
{{Eye procedures}}

{{Authority control}}

[[Category:Diagnostic ophthalmology]]
[[Category:Medical equipment]]
[[Category:Ophthalmic equipment]]