Optic Health Dictionary

A deterioration in the ?bres of the optic nerve (see EYE) resulting in partial or complete loss of vision. It may be caused by damage to the nerve from in?ammation or injury, or the atrophy may be secondary to disease in the eye.... optic atrophy

Otherwise known as the blind spot of the EYE, the disc is the beginning of the optic nerve – the point where nerve ?bres from the retina’s rods and cones (the light- and colour-sensitive cells) leave the eyeball.... optic disc

See EYE.... optic nerve

In?ammation of the optic nerve (see EYE) which may result in sudden loss of part of a person’s vision. It is usually accompanied by pain and tenderness on touch. The cause is uncertain, although in some cases it may be a prcursor of MULTIPLE SCLEROSIS (MS): CORTICOSTEROIDS may help by improving the loss of visual acuity, but seems not to check the long-term in?ammatory activity.... optic neuritis

Someone who ?ts and sells glasses or contact lenses. An ophthalmic optician (optometrist) is trained to perform eye examinations to test for long- and short-sightedness and to prescribe corrective lenses, but they do not treat disorders of the eye, referring patients with a disorder to a family doctor or ophthalmologist.... optician

The transmission of images through bundles of thin, flexible glass or plastic threads which propagate light by total internal reflection. This means that all the light from a powerful external source travels the length of the fibre without losing its intensity. Fibre-optics have led to the development of endoscopes, which enable structures deep within the body to be viewed directly.... fibre-optics

The statutory body that regulates the professions of ophthalmic OPTICIAN (optometrist) and dispensing optician. It promotes high standards of education and professional conduct and was set up by the Opticians Act 1958.... general optical council

This is formed by a crossing-over of the two optic nerves (see EYE) which run from the back of the eyeballs to meet in the mid line beneath the brain. Nerve ?bres from the nasal part of the retina cross to link up with ?bres from the outer part of the retina of the opposite eye. The linked nerves form two separate optic tracts which travel back to the occipital lobes of the brain.... optic chiasma

a rare hereditary disorder, usually affecting young males, that is characterized by loss of central vision due to neuroretinal degeneration. Visual loss in one eye is rapid and usually followed by loss in the second eye. [T. Leber]... leber’s optic atrophy

(Devic’s disease) a condition that resembles multiple sclerosis. The diagnosis is confirmed by the finding of the antiaquaparin-4 antibody (NMO IgG antibody). Typically there is a transverse *myelitis, producing paralysis and numbness of the legs and trunk below the inflamed spinal cord, and *retrobulbar (optic) neuritis affecting both optic nerves. The attacks of myelitis and optic neuritis may coincide or they may be separated by days or weeks. Recovery from the initial attack is often incomplete and severe relapses occur commonly unless treatment with immunosuppressive therapies is started.... neuromyelitis optica

the property possessed by some substances of rotating the plane of polarization of polarized light. A compound that rotates the plane to the left is described as laevorotatory (or l-); one that rotates the plane to the right is described as dextrorotatory (or d-).... optical activity

(OCT) a class of optical tomographic techniques that allows extremely high-quality micrometre-resolution three-dimensional images to be obtained from within optical scattering media (e.g. biological tissue). OCT is proving valuable in ophthalmology, for noninvasive imaging of the ocular structures, and in cardiology for visualizing the interior of coronary arteries using a specialized *catheter. See also spectral domain optical coherence tomography.... optical coherence tomography

(optic commissure) the X-shaped structure formed by the two optic nerves, which pass backwards from the eyeballs to meet in the midline beneath the brain, near the pituitary gland (see illustration). Nerve fibres from the nasal side of the retina of each eye cross over to join fibres from the lateral side of the retina of the opposite eye. The optic tracts resulting from the junction pass backwards to the occipital lobes.... optic chiasm

either of the paired cup-shaped outgrowths of the embryonic brain that form the retina and iris of the eyes.... optic cup

the groove in the top of the *orbit that contains the optic nerve and the ophthalmic artery.... optic foramen

adj. relating to the movements of the eye.... opticokinetic

(Fourier domain OCT) a noncontact noninvasive imaging technique that can reveal layers of the retina by looking at the interference patterns of reflected laser light. Automated software is able to outline the retinal nerve-fibre layer with great precision, which is relevant in glaucoma.... spectral domain optical coherence tomography