ASTIGMATISM

[Whewell], n. ’ma2t-i2zm, Lat., astigmatism us (from a priv., and g7iypa, a spot). Fr., astig matisme, Ger., Astigmatism us. It., Sp., astigmatismo, A state of irregular refraction of an eye, usually congenital, in which the rays of light diverging from a single point can not be brought to a focus at a point on the retina; an asymmetrical condition of the refraction of the different meridians of the eye. [F.]|—Abnormal irregular a. Fr, a stigma tis me irrégulier a normal. Ger., abnormer unregelmä iger Astigmatism us. It., astigmatismo trregolare an or mate. Sp., astigmatismo irregular a normal. A due to some defect in the curvature of the cornea or to some irregularity in the structure or position of the crystalline lens. Meta morpho psi a is the chief symptom. [F.]—Acquired a. Fr., a stigma tis me acquis. Ger., erworbener Astigmatism us. It., astigmatismo acquist a to (0 guadagrato). Sp., astigmatismo adquirido. A. dependent on flattening of the cornea from inflammatory changes, on irregular eppcsltion of the flaps after a cataract extraction, or on dislocation of the crystalline lens. [F.]—Compound hyper metro pie a. Fr., a stigma tis me hypermétropique composé. Ger., zusammengesetzter hyper me trop is cher Astigmatism us. It., astigmatismo tpermetropico compos to. Sp., astigmatismo hipermetrépico comueston That state of refraction in which hypermetropia exists in the two principal meridians, with an additional degree of hypermetropia in one of them; symbol, H+Hm. [F.|—Compound myopic a. Fr., a stigma tis me myopique composé. Ger., zusammengesetzter myopischer Astigmatism us. It., astigmatismo miopico compos to, Sp., astigmatismo miôpico compuesto, That state of refraction in which myopia exists in both princi meridians, with an additional degree of myopia in one of them; symbol, M+Am. [F.]-Corneal a. A. due to causes residing in the cornea. [I.J—Hypermetropic a. Fr., a stigma tis me hypermétropique. Ger., hyper me trop is cher Astigmatism us. It., astigmatismo ipermetropico. Sp., astigmatismo hipermetrépico. See Simple and Compound hypermetropic a.—Irregular a. Fr., a stigma tis me irrégulier. Ger., unregelmé iger Astigmatism us. | It., astigmatismo irregolare. Sp., astigmatismo irregular. See Nor: mat and Abnormal irregular a.—Lenticular a. Fr., a stigma tis me lenticulaire, Ger., Lin sen astigmatism us. A. due to causes residing in the crystalline lens. ea ae a. Fr., a stigma tis me mixte. Ger., gemischter Astigmatism us. It., Sp.,’ astigmatismo mis to. A form of a. in which myopia exists in one principal meridian, and hypermetropia in the other. When there is predominant myopia, its symbol is Amh, and when there is predominant hypermetropia, Ahm. JE Myopte a. Fr., a stigma tis me myopique. Ger., myopischer Astigmatism us. It., astigmatismo miopico. Sp., astigmatismo midpico. See Simple and Compound myopic a.— Normal irregular a. Fr., a stigma tis me irrégulier normal. Ger., unregelma iger normaler Astigmatism us. It., astigmatismo irregolare normale. Sp., astigmatismo irregular normal. A, due to irregularities in the structure and density of the crystalline lens, so that an aberration of the rays occurs as they traverse the different sectors, in consequence of which there is an imperfect coincidence of the images of the different sectors. Its chief symptom is polyopia. [F.J—Regular a. Fr., a stigma tis me régulier. Ger., regelmä iger Astigmatism us. It., astigmatismo regolare. Sp., astigmatismo regular. That error of refraction which is due to a difference in the focal distance of the two princire meridians, and depends mainly on the curvature of the cornea, F.|—Simple by per me tropic a. Fr., a stigma tis me simple hypermétropique. Ger., einfacher hyper me trop is cher A stigma tis- The larva of the fly (various mus. It., astigmatismo ipermetropico semplice, Sp., a stigma tian rmetrépico simple, A. with emmetropia in one of the princi meridians of the eye and TE SN ia in the other: symbol, Ah. [B; imple myopic a. Fr., a stigma tis me simple myopique., einfacher myopischer Astigmatism us. It., astigmatismo miopico semplice. … astigmatismo midpico simple. A. with emmetropia in one of the princij meridians of the eye and myopia in the other; symbol, Am. [B; F]