Ophthalmoscopy

combination by Welch Allyn 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 cataracts. 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 headaches, the finding of swollen optic discs (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 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 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), or by reducing the ophthalmoscope's brightness, which may slightly increase natural mydriasis. 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. 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: 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. 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. 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. 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. 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-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 note. ==See also==