Examples of optic disc in the following topics:
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- Optical discs are digital storing media read in an optical disc drive using laser beam.
- Compact disks (CDs) and digital video disks (DVDs) are examples of optical discs.
- They are read in an optical disc drive which directs a laser beam at the disc.
- Optical discs are digital storing media.
- In this early version of an optical disc, you can see the pits and lands which either reflect back light or scatter it.
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- Consequences of intracranial hypertension: Large tumors or tumors with extensive perifocal swelling (edema) inevitably lead to elevated intracranial pressure (intracranial hypertension), which translates clinically into headaches, vomiting (sometimes without nausea), altered state of consciousness (somnolence, coma), dilation of the pupil on the side of the lesion (anisocoria), papilledema (prominent optic disc at the funduscopic eye examination).
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- The image is transduced into neural impulses and then transferred through the optic nerve to the rest of the brain for processing.
- The optic chiasm is a complicated crossover of optic nerve fibers behind the eyes at the bottom of the brain, allowing the right eye to "wire" to the left neural hemisphere and the left eye to "wire" to the right hemisphere.
- These cues range from the convergence of our eyes and accommodation of the lens to optical flow and motion.
- Clockwise from left: Optic nerve, optic disc, sclera, choroid, retina, zonular fibers, posterior chamber, iris, pupil, cornea, aqueous humor, ciliary muscle, suspensory ligament, fovea, retinal blood vessels.
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- A diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams travelling in different directions.
- Because of this, gratings are often used in monochromators, spectrometers, wavelength division multiplexing devices, optical pulse compressing devices, and many other optical instruments.
- The structure of a DVD is optically similar, although it may have more than one pitted surface, and all pitted surfaces are inside the disc.
- The readable surface of a Compact Disc includes a spiral track wound tightly enough to cause light to diffract into a full visible spectrum.
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- In optical imaging, there is a fundamental limit to the resolution of any optical system that is due to diffraction.
- However, there is a fundamental maximum to the resolution of any optical system that is due to diffraction (a wave nature of light).
- For telescopes with circular apertures, the size of the smallest feature in an image that is diffraction limited is the size of the Airy disc, as shown in .
- The denominator $nsin \theta$ is called the numerical aperture and can reach about 1.4 in modern optics, hence the Abbe limit is roughly d=λ/2.
- There are techniques for producing images that appear to have higher resolution than allowed by simple use of diffraction-limited optics.
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- The floor of the amniotic cavity is formed by the embryonic disc.
- The embryonic disc is derived from the epiblast layer, which lies between the hypoblast layer and the amnion.
- The embryonic disc forms during early development.
- The formation of the bilaminar embryonic disc precedes gastrulation.
- As gastrulation progresses, the embryonic disc becomes trilaminar and the notochord is formed.
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- A disc herniation is a common injury caused by a tear in the fibrous ring of an intervertebral disc, allowing the central portion to bulge.
- A spinal disc herniation is a medical condition affecting the spine in which a tear in the outer, fibrous ring of an intervertebral disc allows the soft, central portion to bulge out beyond the damaged outer rings .
- The condition is widely referred to as a slipped disc, but this term is not medically accurate as the spinal discs are fixed in position between the vertebrae and cannot in fact "slip. " A herniated disc may occur due to trauma, lifting injuries, or other factors.
- If the herniated disc is in the lumbar region (where the majority of herniated discs occur), the patient may also experience sciatica due to irritation of one of the nerve roots of the sciatic nerve.
- In the majority of cases, spinal disc herniation doesn't require surgery.
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- Each of these contributes to the optical resolution of the system, as will the environment in which the imaging is performed.
- Real optical systems are complex, and practical difficulties often increase the distance between distinguishable point sources.
- At very high magnifications with transmitted light, point objects are seen as fuzzy discs surrounded by diffraction rings.
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- The optic nerve is also known as cranial nerve II.
- The optic nerve is the second of twelve paired cranial nerves.
- As a consequence, optic nerve damage produces irreversible blindness.
- The optic nerve leaves the orbit, which is also known as an eye socket, via the optic canal, running posteromedially toward the optic chiasm, where there is a partial decussation (crossing) of fibers from the nasal visual fields of both eyes.
- An illustration of the brain highlighting the optic nerve and optic tract.
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- Development of the optic vesicles starts in the three week embryo from a progressively deepening groove in the neural plate called the optic sulcus.
- As this expands, the rostral neuropore (the exit of the brain cavity out of the embryo) closes and the optic sulcus and the neural plate becomes the optic vesicle.
- The lens acts as an inducer back to the optic vesicle to transform it into the optic cup and back to the epidermis to transform it into the cornea.
- Iris is formed from the optic cup cells.
- After the closure of the tube they are known as the optic vesicles.