Optic disc
Interior of posterior half of bulb of left eye. The veins are darker in appearance than the arteries.
The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section.
Gray's	subject #225 1015
MeSH	Optic+Disk

The optic disc or optic nerve head is the location where ganglion cell axons exit the eye to form the optic nerve. There are no light sensitive rods or cones to respond to a light stimulus at this point thus it is also known as "the blind spot" or "anatomical blind spot"; the break in the visual field created by the optic disc is also called "the blind spot" or "physiological blind spot". The optic nerve head in a normal human eye carries from 1 to 1.2 million neurons from the eye towards the brain. Image File history File links Gray879. ... In biology, a vein is a blood vessel which carries blood toward the heart. ... Section of an artery An artery or arterial is also a class of highway. ... Image File history File links Gray880. ... MRI scan of human eye showing optic nerve. ... Wikipedia does not yet have an article with this exact name. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A ganglion cell (or sometimes called a gangliocyte) is a type of neuron located in the retina that receives visual information from photoreceptors via various intermediate cells such as bipolar cells, amacrine cells, and horizontal cells. ... A human eye. ... MRI scan of human eye showing optic nerve. ... A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eyes retina that is capable of phototransduction. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength[1]. The elementary particle that defines light is the photon. ... The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. ... A blind spot, also known as a scotoma, is an obscuration of the visual field. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ...

Clinical examination

The eye is unique due to the transparency of its optical medium. Almost all eye structures can be examined with appropriate optical equipment and lenses. Using a modern direct ophthalmoscope gives a view of the optic disc using the principle of reversibility of light. A slit lamp biomicroscopic examination along with an appropriate aspheric focusing lens (+66D, +78D or +90D) is required for a detailed stereoscopic view of the optic disc and structures inside the eye. Inspection of the optic disc by ophthalmoscopy or biomicroscopy can give an indication of the health of the optic nerve. In particular, the eye care physician notes the colour, cupping size (as a ratio of the cup to disc size), sharpness of edge, swelling, hemorrhages, notching in the optic cup and any other unusual anomalies. It is useful for finding evidence corroborating the diagnosis of glaucoma and other optic neuropathies, optic neuritis, anterior ischemic optic neuropathy or papilledema (i.e. optic disc swelling produced by raised intracranial pressure). Women in advanced stage of pregnancy with pre-eclampsia should be screened by an ophthalmoscopic examination of the optic disc for early evidence of rise in intracranial pressure. The ophthalmoscope, invented by Hermann von Helmholtz, is an instrument used to examine the eye. ... The slit-lamp examination looks at structures that are at the front of the eye (the anterior segment): The eyelid, the sclera (white outer structure of the eye), conjunctiva (membranes lining the eyelid and sclera surface), iris (colored part of the eye), natural crystalline lens, and the cornea (thin transparent... Traditional Snellen chart used for visual acuity testing. ... In medicine the ophthalmoscope was invented by Hermann von Helmholtz and is an instrument that is used to look into the human eye. ... The slit-lamp examination looks at structures that are at the front of the eye (the anterior segment): The eyelid, the sclera (white outer structure of the eye), conjunctiva (membranes lining the eyelid and sclera surface), iris (colored part of the eye), natural crystalline lens, and the cornea (thin transparent... Optic [[neuritis](or retrobulbar neuritis) is the inflammation of the optic nerve that may cause a complete or partial loss of vision. ... Anterior ischemic optic neuropathy (AION) is a medical condition involving loss of vision due to damage to the optic nerve from insufficient blood supply. ... Papilledema is optic disc swelling that is caused by increased intracranial pressure. ... Intracranial pressure, (ICP), is the pressure exerted by the cranium on the brain tissue, cerebrospinal fluid (CSF), and the brains circulating blood volume. ... Pre-eclampsia is said to be present when hypertension arises in pregnancy (pregnancy-induced hypertension) in association with significant protein in the urine. ... Intracranial pressure, (ICP), is the pressure exerted by the cranium on the brain tissue, cerebrospinal fluid (CSF), and the brains circulating blood volume. ...

Schematic diagram of the human eye, with the optical disc, or blind spot, at the bottom.

Image File history File links Schematic_diagram_of_the_human_eye_en. ... Image File history File links Schematic_diagram_of_the_human_eye_en. ...

Imaging of the optic disc

Traditional color-film camera images are the gold standard in imaging, requiring an expert ophthalmic photographer, ophthalmic technician or an ophthalmologist for taking standardised pictures of the optic disc. Stereoscopic images offer an excellent investigative tool for serial follow-up of suspected changes in the hands of an expert ophthalmologist. However, since not everybody can be trained so well, automated techniques have been devised to supplant or replace the human expertise. Heidelberg Retinal Tomography (HRT-II), GDx-VCC and optical coherence tomography (Stratus-OCT 3) are the currently available computerised techniques for imaging various structures of the eyes, including the optic disc. They quantitate the nerve fiber layer of disc and surrounding retina and statistically correlate the findings with a database of previously screened population of normals. They are useful for baseline and serial follow-up to monitor minute changes in optic disc morphology. It should be noted that imaging won't provide conclusive evidence for clinical diagnosis however, and the evidence needs to be supplanted by serial physiological testing for functional changes. Such tests may include visual field charting, and final clinical interpretation of the complete eye examination by an eye care physician. Ophthalmologists and Optometrists are able to provide this service. GDx-VCC is a diagnostic machine for examining the thickness of the retinal nerve fiber layer by means of laser opthalmoscopy. ... Optical coherence tomography (OCT) is an interferometric, non-invasive optical tomographic imaging technique offering millimeter penetration (approximately 2--3 mm in tissue) with sub-micrometre axial and lateral resolution. ... Morphology is the following: In linguistics, morphology is the study of the structure of word forms. ... Traditional Snellen chart used for visual acuity testing. ...

Retinography photograph showing the optic disc as a bright area on the right where blood vessels converge.

Image File history File links Download high-resolution version (1554x1580, 326 KB) self made retinography File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Optic disc ... Image File history File links Download high-resolution version (1554x1580, 326 KB) self made retinography File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Optic disc ...

External links

• Diagram at Moorfields Eye Hospital
• Diagram at Ballard Optical