opsiometer (opsiometer)

[ ocular, and eyel.] I. a. 1. Relating or pertaining to vision or sight; visual; subservient to the faculty or function of seeing. IMG:content-1774.png:[blocks in formation] 2. Of or pertaining to the eye as the organ of vision; ocular; ophthalmic.-3. Relating to the science of optics. Where our master handleth the contractions of pillars, we have an optick rule that the higher they are the le should be always their diminution aloft, because the eye itself doth naturally contract all objects, more or le , according to the distance. Sir H. Wotton, Elem. of Architecture, i. Basal optic ganglion. See ganglion. - Brachia of the optic lobes. See brachium. - Dispersion of the optic axes. See dispersion. Optic angle. (a) The angle included between the two lines drawn from the two extremities of an object to the first nodal point of the eye; the visual angle. (b) The angle which the visual axes of the eyes make with one another as they tend to meet at some distance before the eyes. (c) The angle between the optic axes in a biaxial crystal. - Optic axis. (a) See arisl. (b) The line in a doubly refracting crystal in the direction of which no double refraction occurs. Crystals belonging to the tetragonal and hexagonal systems have a single optic axis, coincident with their vertical crystal log rap hi cal axis: hence they are said to be uniaxial. Crystals belonging to dainty, in a more general sense meat, flesh, the orthorhombic, monoclinic, and triclinic systems have orig. boiled meat ( two optic axes, and hence are biaxial. - Optic chiasm, in an at., the commi ure, decu ation, or chiasm of the right and left optic nerves. See chiasm, and cuts under brain and corpus. - Optic commi ure. Same chiasm.