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Ophthalmoscopy, also called funduscopy, is a test that allows a health professional to see inside the fundus of the eye and other structures using an ophthalmoscope (or funduscope). It is done as part of an
eye examination An eye examination, commonly known as an eye test, is a series of tests performed to assess Visual acuity, vision and ability to Focus (optics), focus on and discern objects. It also includes other tests and examinations of the human eye, eyes. ...
and may be done as part of a routine
physical examination In a physical examination, medical examination, clinical examination, or medical checkup, a medical practitioner examines a patient for any possible medical signs or symptoms of a Disease, medical condition. It generally consists of a series of ...
. It is crucial in determining the health of the
retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
,
optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form t ...
, and vitreous humor. The
pupil The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black becau ...
is a hole through which the eye's interior can be viewed. For better viewing, the pupil can be opened wider (dilated;
mydriasis Mydriasis is the Pupillary dilation, dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, Physical trauma, trauma, or the use of c ...
) before ophthalmoscopy using medicated
eye drop Eye drops or eyedrops are liquid drops applied directly to the surface of the eye usually in small amounts such as a single drop or a few drops. Eye drops usually contain saline to match the salinity of the eye. Drops containing only saline ...
s (
dilated fundus examination Dilated fundus examination (DFE) is a diagnostic procedure that uses mydriatic eye drops to dilate or enlarge the pupil in order to obtain a better view of the fundus of the eye. Once the pupil is dilated, examiners use ophthalmoscopy to view ...
). However, undilated examination is more convenient (albeit not as comprehensive), and is the most common type in
primary care Primary care is a model of health care that supports first-contact, accessible, continuous, comprehensive, and coordinated person-focused care. It aims to optimise population health and reduce disparities across the groups by ensuring equitable ...
. An alternative or complement to ophthalmoscopy is to perform a fundus photography, where the image can be analysed later by a professional.


Types

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 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. 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 of the eye, even if the lens is clouded by
cataract A cataract is a cloudy area in the lens (anatomy), lens of the eye that leads to a visual impairment, decrease in vision of the eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or ...
s. 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 A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...
s, the finding of swollen
optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form t ...
s (
papilledema Papilledema or papilloedema is optic disc swelling that is caused by increased intracranial pressure due to any cause. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare. In ...
) on ophthalmoscopy is a key sign indicating raised
intracranial pressure Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury ( mmHg) and at rest, is normally 7–15 mmHg for a supine adu ...
, which may be due to conditions such as
hydrocephalus Hydrocephalus is a condition in which cerebrospinal fluid (CSF) builds up within the brain, which can cause pressure to increase in the skull. Symptoms may vary according to age. Headaches and double vision are common. Elderly adults with n ...
, benign intracranial hypertension (pseudotumor cerebri), and
brain tumors A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign (non-cancero ...
. In glaucoma, cupped optic discs are seen. In patients with
diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...
, regular ophthalmoscopic eye examinations (once every 6 months to 1 year) are important to screen for
diabetic retinopathy Diabetic retinopathy (also known as diabetic eye disease) is a medical condition in which damage occurs to the retina due to diabetes. It is a leading cause of blindness in developed countries and one of the lead causes of sight loss in the wor ...
, 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 predict cerebrovascular accidents (strokes).


Dilating the pupil

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 mydriatic agent (e.g.
tropicamide Tropicamide, sold under the brand name Mydriacyl among others, is a medication used to dilate the pupil and help with the examination of the eye. Specifically it is used to help examine the back of the eye. It is applied as eye drops. Effect ...
), or by reducing the ophthalmoscope's brightness, which may slightly increase natural
mydriasis Mydriasis is the Pupillary dilation, dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, Physical trauma, trauma, or the use of c ...
. 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 , so dilating the pupil is not necessary with these methods.


History


Early models

The first instrument for looking into the eye was first invented in 1847 by British inventor
Charles Babbage Charles Babbage (; 26 December 1791 – 18 October 1871) was an English polymath. A mathematician, philosopher, inventor and mechanical engineer, Babbage originated the concept of a digital programmable computer. Babbage is considered ...
. However, he was unable to obtain an image with the instrument when showing it to ophthalmologist
Thomas Wharton Jones Thomas Wharton Jones (9 January 1808 – 7 November 1891) was a ophthalmologist and physiologist of the 19th century. Biography Jones's father was Richard Jones, a native of London. Richard Jones had moved north to St Andrews and was working w ...
, and thus became discouraged to proceed further. The instrument is described by Jones as follows: Later in 1851, German physiologist
Hermann von Helmholtz Hermann Ludwig Ferdinand von Helmholtz (; ; 31 August 1821 – 8 September 1894; "von" since 1883) was a German physicist and physician who made significant contributions in several scientific fields, particularly hydrodynamic stability. The ...
invented the ophthalmoscope again independently. At that time, Helmholtz was a young
physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...
professor and wanted to demonstrate to his students why the
pupil The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black becau ...
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): * 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 Helmholtz called his instrument an ('eye mirror'). The name "ophthalmoscope" only came into common use in 1854, three years after the instrument's invention.


Later improvements

Helmholtz's first ophthalmoscope could not correct for
refractive errors Refractive error is a problem with focus (optics), focusing light accurately on the retina due to the shape of the eye and/or cornea. The most common types of refractive error are myopia, near-sightedness, hyperopia, far-sightedness, astigmatis ...
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. 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 Beale) created ophthalmoscopes with an attached light source. While training in France, Greek ophthalmologist Andreas Anagnostakis came up with the idea of making the instrument hand-held by adding a
concave mirror A curved mirror is a mirror with a curved reflecting surface. The surface may be either ''convex'' (bulging outward) or ''concave'' (recessed inward). Most curved mirrors have surfaces that are shaped like part of a sphere, but other shapes are ...
. Austin Barnett created a model for Anagnostakis, which he used in his practice and subsequently presented at the first Ophthalmological Conference in
Brussels Brussels, officially the Brussels-Capital Region, (All text and all but one graphic show the English name as Brussels-Capital Region.) is a Communities, regions and language areas of Belgium#Regions, region of Belgium comprising #Municipalit ...
in 1857, which made the instrument very popular among ophthalmologists. The invention of the
incandescent light bulb An incandescent light bulb, also known as an incandescent lamp or incandescent light globe, is an electric light that produces illumination by Joule heating a #Filament, filament until it incandescence, glows. The filament is enclosed in a ...
further enabled the ophthalmoscope to be self-luminous instead of relying on an external and remote source of illumination. 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. 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. In 1915, Francis A. Welch and William Noah Allyn invented the world's first hand-held direct-illuminating ophthalmoscope. The company
Welch Allyn Welch Allyn, Inc. is an American manufacturer of medical devices and patient monitoring systems. Headquartered in Skaneateles Falls, New York, it was family-owned until it was acquired in 2015 by Hillrom. Hillrom was purchased by Baxter In ...
started as a result of this invention. 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.


Etymology and pronunciation

The word ''ophthalmoscopy'' () uses combining forms of '' ophthalmo-'' + '' -scopy'', yielding "viewing the eye". The word ''funduscopy'' () derives from '' fundus'' + '' -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
descriptive In the study of language, description or descriptive linguistics is the work of objectively analyzing and describing how language is actually used (or how it was used in the past) by a speech community. François & Ponsonnet (2013). All aca ...
-versus- prescriptive difference in acceptance. Some dictionaries enter the ''fundo-'' form as a second-listed variant, but others do not enter it at all, and one prescribes its avoidance with a
usage The usage of a language is the ways in which its written and spoken variations are routinely employed by its speakers; that is, it refers to "the collective habits of a language's native speakers", as opposed to idealized models of how a languag ...
note.


See also

* Charles Schepens *
Retinoscope Retinoscopy is a technique to obtain an objective measurement of the refractive error of a patient's eyes. How It Works The examiner uses a retinoscope to shine light into the patient's eye and observes the reflection (reflex) off the patient' ...
*
Scanning laser ophthalmoscopy Scanning laser ophthalmoscopy (SLO) is a method of examination of the eye. It uses the technique of confocal laser scanning microscopy for diagnostic imaging of the retina or cornea of the human eye. As a method used to image the retina with a ...


References


External links


Ophthalmoscopy on Medlineplus

Ophthalmoscopy on WebMD

Overview at bmjjournals.com


about different types of ophthalmoscopy {{Authority control Diagnostic ophthalmology Medical equipment Ophthalmic equipment