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Optic nerve
Optic nerve Sensory nerve that transmits impulses from the retina to the brain that become what we know as vision.
RELATED TERMS--------------------------------------
Nerve
Tissue that conveys sensation, temperature, position information to the brain.
Retina
A membrane lining the inside of the back of the eye that contains light-sensitive nerve cells that convert focused light into nerve impulses, making vision possible.
Brain
"That part of the central nervous system that is located within the cranium (skull). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called ""hemispheres."" "
Vision
The sense of sight.
SIMILAR TERMS--------------------------------------
Optic atrophy
A disease of the optic nerve in which the nerve fibers carrying the electrical impulses from the eye to the brain start to die off. In such cases the optic nerve has a pale or whitish appearance compared to the normal pink color. Optic atrophy is associated with poor reading vision and often the cause of legal blindness. May be associated with a serious medical condition and requires further medical examination to determine the cause of the atrophy. Not reversible.
Optic chiasm
Location where the optic nerve axons from the two retinae join and are reorganized into two separate groups (the optic tracts) that encode information about the right and left visual fields.
Optic disc
The visible part of the optic nerve inside the eye. The axons of the ganglion cells of the inner retina make-up the optic nerve.
Optic disk
Where the ganglion cell axon fibers leave the retina. Contains no photoreceptors and therefore creates a blind spot in the visual field.
Optic nerve hypoplasia
small and underdeveloped optic nerve. Optic nerve hypoplasia is one of the leading causes of vision loss and blindness in infants and children. Optic nerve hypoplasia occurs in the early stages of fetal development, when the eyes are forming. The optic nerve never fully develops or, once developed, dies-off and reduces in size for unknown reasons. Recent evidence suggests that ganglion cell axons, that make-up the optic nerve, are not able to grow through the optic nerve head because certain chemical messengers are not present for directional growth from the eye to the brain. Optic nerve hypoplasia is variable, and can result in only minor vision problems to complete blindness. Usually, if the infant has nystagmus the optic nerve hypoplasia is more severe and vision is very much reduced. If the infant does not have nystagmus, the likelihood for significant vision loss in less. All infants with optic nerve hypoplasia should have a CT scan or MRI to look for midline brain defects that can result in body growth problems. If the infant does not have nystagmus, the chance of midline brain defects is small. If the infant has nystagmus, the chance of midline defects is greater. Some infants have optic nerve hypoplasia in one eye only. If only in one eye, the chance of midline defects is very small and the doctor may chose not to do a CT scan or MRI, depending on other factors. There is no treatment or cure for optic nerve hypoplasia.
Optic nerves
Myelinated axons from the optic disk of each eye which join at the optic chiasm.
Optic neuritis
Optic neuritis
An inflammation of the optic nerve usually with some loss of sight (may be temporary). It may signify a more serious neurological condition. A leading cause of optic neuritis is multiple sclerosis (MS).
Optic radiations
Projections from LGN to primary visual cortex (V1).
Optic tectum
Structure in the mid-brain of cold-blooded vertebrate that receives input from the optic nerve (homologous to the superior colliculi).
Optic tract
Retinal fibers leaving the optic chiasm separated by visual hemi-field (i.e. not by eye). Projects to three areas, the pretectum, the superior colliculus and the LGN.
Optical
Having to do with vision.
Optical power (of a lens)
Measure of how strongly a lens bends incoming rays. Measured in diopters and equal to the reciprocal of focal length. Human eye has an optical power of about 58.8 diopters.
Optician
A technician who fits a person for glasses. He/she does not test for glasses. Some opticians also fit contact lenses.
Opticrom
Opticrom is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): cromolyn sodium.
Optimark
Optimark is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): gadoversetamide.
Optimark in plastic container
Optimark in plastic container is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): gadoversetamide.
Optimine
Optimine is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): azatadine maleate.
Optipranolol
Optipranolol is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): metipranolol hydrochloride.
Optiray 160
Optiray 160 is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): ioversol.
Optiray 240
Optiray 240 is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): ioversol.
Optiray 300
Optiray 300 is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): ioversol.
Optiray 320
Optiray 320 is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): ioversol.
Optiray 350
Optiray 350 is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): ioversol.
Optison
Optison is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): albumin human.
Optivar
Optivar is a prescription or over-the-counter drug which is (or once was) approved in the United States and possibly in other countries. Active ingredient(s): azelastine hydrochloride.
PREVIOUS AND NEXT TERMS--------------------------------------
Organism
A living thing, such as an animal, a plant, a bacterium, or a fungus.
Orgasm
An intense sensation that occurs at the climax of sexual excitement that is accompanied by rhythmic muscle contractions and intense pleasure, followed by release of sexual tensions. In men, orgasm is usually accompanied by ejaculation.
Organic
Of or related to a substance that contains carbon atoms linked together by carbon-carbon bonds. All living matter is organic. The original definition of the term organic related to the source of chemical compounds, with organic compounds being those carbon-containing compounds obtained from plant or animal sources, whereas inorganic compounds were obtained from mineral sources. Compounds containing bonds between carbon atoms can now be made in the laboratory and industrially by man.
Omega-3 Fatty Acids
A special type of polyunsaturated essential fatty acids found primarily in cold-water fish and purified fish oils. This type of fat is exceptionally beneficial to your cardiovascular system because of its effect on promoting the formation of "good" eicosanoids.
Omega-6 Fatty Acids
The type of polyunsaturated fatty acids found in protein and most seed oils. This type of fat can generate both "good" and "bad" eicosanoids.
Optic nerve
Osteoporosis
Break-down or disintegration of bone, resulting in diminished and porous bone mass. Osteoporosis can result from cancer (including breast cancer) that has spread to the bones), some cancer therapies, and estrogen deficiency (estrogen is an important participant in maintaining bone). Osteoporosis can cause pain, deformity (especially of the spine), pathologic fractures (fractures caused by weakened bone), or traumatic fractures (for example, wrist or hip fracture from a fall).
Osteosarcoma
Osteosarcoma is the most common primary malignant bone tumour, excluding myeloma and lymphoma. There is a predilection for the metaphyseal region of tubular long bones. 50% of cases occur around the knee. It is a cancer that usually affects the large bones of the arm or leg. It occurs most commonly in young people and affects more males than females. Also called osteogenic sarcoma.
Ovaries
The paired female sex glands in the pelvis, located one on each side of the uterus. The ovaries produce eggs and hormones including estrogen, progesterone, and androgens.
Osteoarthritis
Degenerative disorder of joints, most often from disease in the spine and in the weight bearing joints (knees and hips). Normally seen with aging, but can occur prematurely due to various reasons, for instance after an injury to a joint. Also known as degenerative joint disease, it can cause joint pain, loss of function, reduced joint motion, and deformity.
Obesity
Abnormal body weight, usually defined as more than 20 percent above average for age, height and bone structure.
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