(a.) Of or pertaining to the eye; ocular; as, the optic nerves (the first pair of cranial nerves) which are distributed to the retina. See Illust. of Brain, and Eye.
(a.) Relating to the science of optics; as, optical works.
Example Sentences:
(1) Following central retinal artery ligation, infarction of the retinal ganglion cells was reflected by a 97 per cent reduction in the radioactively labeled protein within the optic nerve.
(2) This study examined both the effect of variations in optical fiber tip and in light wavelength on laser-induced hyperthermia in rat brain.
(3) The number of axons displaying peptide-like immunoreactivity within the optic nerve, retinal or cerebral to the crush, and within the optic chiasm gradually decreased after 2-3 months.
(4) Once the normal variations are mastered, appreciation of retinal, choroidal, optic nerve, and vitreal abnormalities is possible.
(5) Chromatolysis and swelling of the cell bodies of cut axons are more prolonged than after optic nerve section and resolve in more central regions of retina first.
(6) CW Nd:YAG light transmitted by fiber optic cable and sapphire crystal was applied transsclerally to the ciliary body of pigmented and albino rabbits.
(7) Unlike results seen in the goldfish optic nerve, injury to the rat optic nerve induced no observable increase in laminin content or change in its distribution.
(8) This is the first report of anterior ischemic optic neuropathy as a result of hemodialysis-associated hypotension.
(9) It is shown that, by comparison of a reacting mixture at chemical equilibrium with a non-reacting but equally composed one, the sum of the mean concentrations of the reaction products can immediately be taken from optical absorption or from interferometric measurements.
(10) A television camera scans the spread through microscope optics; computer and special purpose electronics process the video signals to generate run length histograms.
(11) The purity and configuration of each isomer of the free acid and N-chloroacetylated derivative were ascertained by: (a) paper chromatography in five solvent systems, (b) elemental analysis, (c) Van Slyke nitrous acid determination of alpha-carbonyl carbon, and (d) Van Slyke ninhydrin determination of alpha-carbonyl carbon, and (e) optical rotation.
(12) The optical and oxygen binding properties of the reconstituted myoglobins containing two isomeric monoformyl-monovinylhemins were found to be different.
(13) These images were previously determined by using a recently developed hybrid optical-digital method.
(14) The development of optical fibers capable of transmitting laser energy has encouraged the experimental use of laser irradiation for the treatment of acquired cardiovascular disorders.
(15) This technique is sensitive to the optical anisotropy within the muscle, including that due to intrinsic properties of the protein molecules as well as that due to the regular arrangement of proteins in the surrounding medium.
(16) Patients should be evaluated by perimetry using an appropriate strategy and contrast sensitivity testing, along with careful examination of the optic discs.
(17) Thus, during treatment with ethambutol visually (pattern) evoked potentials may reveal a surprisingly high percentage of subclinical optic neuritis.
(18) The optical efficiencies are similar and depend on the match of the excitation characteristics of the stain with the emission spectra of the light source.
(19) Morphological results demonstrated that 30 Gy irradiated animals showed extensive necrosis primarily in the fimbria, which extended into the internal capsule, optic nerve, hippocampus, and thalamus.
(20) A compact attachment for microscope-type instruments is described enabling to introduce, rapidly and qualitatively, minute biological speciments into melted embedding medium and ensuring the safety of optics.
Phosphene
Definition:
(n.) A luminous impression produced through excitation of the retina by some cause other than the impingement upon it of rays of light, as by pressure upon the eyeball when the lids are closed. Cf. After-image.
Example Sentences:
(1) Excitatory (positive) phenomena are subjective photic sensations (phosphenes) which can be elicited by transcranial magnetic stimulation over occipital parts of the skull.
(2) Stimulation substantially above threshold may produce a second conjugate phosphene, inverted about the horizontal meridian.8.
(3) Phosphenes appear immediately when stimulation is begun, and disappear immediately upon cessation of stimulation.18.
(4) The position of phosphenes in the visual field corresponds only roughly with expectations based on classical maps showing the projection of the visual field onto the cortex.14.
(5) The configuration of the phosphene fields hints at an excitation of the primary visual cortex (Brodmann's area 17).
(6) A visual prosthesis based on electrical stimulation of the visual cortex with an array of penetrating electrodes is expected to produce pixelized visual images consisting of punctate spots of light (phosphenes).
(7) The findings of these examinations correlated best of all with the clinical picture when visual evoked potentials (latency increase, decrease of the amplitude with atrophy augmentation, interhemispheric asymmetry in chiasmal and retro-chiasmal involvement) or the critical frequency of phosphene disappearance (reliably reduced if a disease was developing) were recorded.
(8) The phenomenon of deformation phosphenes was instrumental in prompting some pre-Socratic philosophers and Plato to conceive the idea that efferent light is emitted from the eye for the purpose of vision and a 'cone of vision' is formed by interaction with the external light.
(9) Because of the variation in repeated observations of the same phosphene pair, some method is needed to provide the 'best' fitting map to the observations.
(10) The increment threshold for a small spot of light on the phosphene in the dark is some 0.5 log td higher than for the same spot on a patch of light matched in appearance to the phosphene under the same conditions.5.
(11) Our findings indicate that the psychological component of the perception of electric and magnetic phosphenes must not be underestimated.
(12) For cortical phosphenes there is no sharp flicker fusion frequency, and probably no flicker fusion frequency at all.7.
(13) From experimental work on humans in 1905 with unencapsulated radium, it is known that approximately 80% of the intensity of the radium phosphene is from the beta-ray component and approximately 20% from the gamma-ray.
(14) Experiments are described in which the phosphene produced by passing alternating current of frequency 100 Hz through the eye is matched with a patch of light having the same apparent size.2.
(15) The prosthesis would create a pixelized visual sense consisting of punctate spots of light (phosphenes).
(16) The phosphenes appear on the left or right side of the visual field depending upon the direction of the coil currents, which determines whether the visual cortex of the right or the left hemisphere is activated.
(17) Electrical stimulation of the occipital cortex resulted in discrete photic sensations or "phosphenes" in two volunteers who had been totally blind for 7 and 28 years, respectively.
(18) Patterns of up to four phosphenes produced by four electrodes have been recognized.
(19) The influence of coil position on the size of electromyographic responses and on the intensity and position of phosphenes in the binocular visual field was studied.
(20) In the medial area (10-15 mm from the midline) of the occipital lobe, stimuli above the calcarine fissure resulted in phosphenes in the lower quadrant of the visual field.