| DOS | day of surgery; deoxystreptamine; disk operating system; Doctor of Ocular Science; Doctor of Optical... |
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| IOD | injured on duty; integrated optical density; interorbital distance |
| MORD | magnetic optical rotatory dispersion |
| OCR | oculocardiac reflex; oculocerebrorenal [syndrome]; optical character recognition |
| OD | Doctor of Optometry; obtained absorbance; occipital dysplasia; occupational dermatitis; occupational... |
| optical sectioning | <microscopy> The use of high numerical aperture objective and condenser lenses on a microscope to achieve a shallow depth of field. With a very shallow depth of field, objects above and below focus contribute little to the in-focus image, so that a clean optical section is obtained. See: depth of field. (05 Aug 1998) |
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| optical staining | <microscopy> Producing colour in the microscopical image so as to differentiate one part of the object from another. One way is by use of Rheinberg filters. Another is to use polarized light on an anisotropic specimen. Another important method is by dispersion staining. (05 Aug 1998) |
| optical storage devices | A computer disk read by a laser beam, containing data prerecorded by a vendor. The buyer cannot enter or modify data in any way but the advantages lie in the speed of accessibility, relative immunity to damage, and relatively low cost of purchase. (12 Dec 1998) |
| optical transfer function | <microscopy> The relationship between the image produced by an optical instrument and the amplitude and phase of a periodic specimen, measured at various spatial frequencies. The optical transfer function curve, which shows how well contrast is maintained for finer specimen details, is a complex function, of which the real term gives the ratio of amplitudes, and the imaginary term the phase relationships. When the brightness of the periodic specimen varies as a sine wave, the modulus or absolute value of the optical transfer function becomes the modulation transfer function, when the brightness varies as a square wave, the modulation transfer function is known as a contrast transfer function. Acronym: OTF (26 Mar 1998) |
| optical tubelength | <microscopy> The distance from the second principal focal plane of the objective to the front focal plane of the ocular. This distance is about 180 mm for high-power objectives, less for those of low power. (05 Aug 1998) |
| electron optical axis | <physics> The path of an electron through an electron optical system along which it suffers no deflection due to lens fields. This axis does not necessarily coincide with the mechanical axis of the system. (05 Aug 1998) |
| electron optical system | <apparatus> A combination of parts capable of producing and controlling a beam of electrons to produce an image of an object. (05 Aug 1998) |
| tubelength optical | <microscopy> This distance is measured from the upper focal plane of the objective to the image formed by the objective alone upon removal of the eyepiece. A light microscope so arranged that the specimen, usually a solid-liquid colloid or suspension, is illuminated by a strong pencil of light at right angles to the microscope axis. The visibility is limited by the intensity of the light source. A laser can be used as the source. It is used to detect the presence of light-ultramicroscopic particles within the range of about 0.005,um to 0.2 ~m. Not to be confused with an electron microscope. (05 Aug 1998) |
| ganglion cells of retina | The nerve cell's of the retina whose central processes (fibres) form the optic nerve; their peripheral processes synapse with the bipolar cell's and through them with the rod and cone cell's; these cell bodies are round or flask-shaped and vary considerably in size. (05 Mar 2000) |
| ganglionic layer of retina | The intermediate layer of neurons in the retina composed largely of bipolar cells. Synonym: internal nuclear layer of retina, stratum ganglionare retinae, stratum nucleare internum retinae. (05 Mar 2000) |
| medial arteriole of retina | An arteriole supplying the part of the retina between the optic disk and the macula. Synonym: arteriola medialis retinae. (05 Mar 2000) |
| medial venule of retina | The small vein that passes from the part of the retina between the macula and the optic disk to join the central vein. Synonym: venula medialis retinae. (05 Mar 2000) |
| central artery of retina | A branch of the ophthalmic artery which penetrates the optic nerve 1 cm behind the eye to enter the eye at the optic papilla in the retina; it divides into superior and inferior temporal and nasal branches. Synonym: arteria centralis retinae, arteria retinae centralis, Zinn's artery. (05 Mar 2000) |
| central vein of retina | Formed by union of the retinal veins and accompanies the artery of the same name in the optic nerve. Synonym: vena centralis retinae. (05 Mar 2000) |
| cerebral layer of retina | The internal layer of the retina containing the neural elements, as distinguished from the outer leaf of the retina, or pigmented layer. Synonym: pars optica retinae, neural layer of retina, optic part of retina, stratum cerebrale retinae. (05 Mar 2000) |