ACCOMBANT

(Fr.), adj. A*k-kom-baën?, Accumbent. [B.] ACCOMMODATION, n. A°k-ko?m-mo-da’shu?n. Lat., accommodatio (from accommodare, to adapt, to adjust). Fr., accommodation. Ger., Accommodation. It., accomm: lone. Sp., acomodaciôn. 1. The proce by which the refractive condition of the eye is changed in accordance with the distance at which an object is to be viewed, so as to secure invariable focusing of the iene on the retina. {F.] 2. The proce es by which a partly disabled organ is favored in the performance of its functions. See Compensation. 3. The adjustment of the shape and attitude of the foetus to the parturient canal during labor.—A’sbezirk, (Ger.). See Amplitude of a.—A’simpuls (Ger.). That condition in which the eye feels the nece ity of a. in order to see more distinctly. [F.]—A’skrampf (Ger.). See Spasm of a.—A’slinie (Ger.). See Line of a.—A’smuskel (Ger.). See Ciliary muscLe.—A’sphosphen (Ger.). See PHOSPHENES of a, —A’ pannung (Ger.). See Tension of a.—A's vermigen (Ger.). The accommodative power of the eye —Amplitude of a. Fr., amplitude (ou étendue) d’a. Ger.,. It., ampiezza d’accommodazione. Sp., amplitud (0 extension) de acomodaciôn. The amount of accommodative effort of which the eye is capable, from its far point up to its near point. {F.]—Asthenopia of a. See Accommodative ASTHENOPIA.—Binocular a. Fr., a, binoculaire. Ger., binoculäre A. It., accommodazione binocula. Sp., acomodacién binocular. The power of the two eyes, when used together, of focusing the images of objects on the ret inæ of both for all distances. [F.]—Breadth of a. See Range of a.— THE MECHANISM OF ACCOMMODATION. , cornea; 4, iris; 2, lens during repose; ¢, #,, the same parts during an effort of ‘accommodation. Étendue d’a. (Fr). See Amplitude of a.—Étendue latente d’a. (Fr.), See Latent HYPERUFTROPIA.—Kreis der A. (Ger.). See Region of a.—Latent range of a. Fr., étendue latented’a. Ger., latente A’sbreite. It., campo (0 est ens i one) latente d’accommodazione. Sp., campo latente de acomodaciôn. See Latent HYPER- METROPIA.—Line of a. Fr., ligne d’a. Ger., A’slinie, It., tinea d'accommodazione. Sp., line a de acomodacién. Czermak’s term for that portion of the visual line (q. v under Liye) in which lie objects which are seen without any perceptible indistinctne , and with a given state or degree of a, [F.|—Mechanism ofa. Fr., mécan is me d’a. Ger.,. It., meccanismo d’accommodazione. Sp., mecanismo de acomodaciôn. A term used to signify not only the manner in which a, takes place, but also the structures by Which it is accomplished (the ciliary muscle, the zonule of Zinn, and the crystalline lens).—Negative a. Fr., a. négative. Ger., negabive A. It., accommodazione negativa. fS L acomodacién negativa. It is supposed by some that, when the emmetropic eye is in a state of rest, it is not quite adjusted for its farthest point of distinct vision, but can become so by a slight alteration in its a., which is called negative, produced, acco! to Henke, by the action of the radial fibers of the ciliary muscle. —Negative range of a. See So of a.—Paralysis of a. under ParaLysis.—Phosphenes of a.. See under PHosPHENE.— Positive a., Positive range of a., Positive relative range of a See Range of a—Range ofa. Fr., amplitude (ou champ, ou étendue) d’a. Ger.,. It., ampiezza (0 campo) d’accommodazione, Sp.,campo de acomodacion. The distance between the farthest point and the nearest point of distinct vision. It is expre ed by the formula 5 — Fr in which P represents the near point and R the far point; and may be taken as the difference in refractive power of lenses of which the foci are res} ‘ively P and R. The binocular range of a. is the a. from the farthest point (ry) to the nearest point (pz), for both eyes at once. The relative range of a. is the range over which we have control at a given convergence of the visual lines, It represents the degree in which a. is independent of convergence. The positive relative range of a. represents the amount of a. of which a person is capable nearer or closer than the point of convergence of the visual lines of the eyes. The negative relative range of a. is that amount of convergence which is required in order that a person may clearly see an object lying beyond the point of convergence of the visual lines. [F. egion of a, Fr., région d’a. Ger.,. It., regione d’accommodazione. BP reg iôn de acomodaciôn. According to Donders, this is only the expre ion of the distance between r and p, and is therefore equal to R—P, while the range of a. (g. v.) is a dioptric value, proportional to the focal distance of the lens, which expre es the difference of a. for Pand R. The region of a. 1s quite altered by spectacles, and there is no proportion whatever between it and the range of a. [F.|—Relative range of a. See Range of a. —Spasm ofa. See under SpasM.—Tension of a. Ger.,. Syn.: amount (or degree) of a. The act of tension or contraction of the ciliary muscle; also that condition or degree of a. which aes along with a given degree of convergence of the ocular axes. [F.