. On the anomalies of accommodation and refraction of the eye, witha preliminary essay on physiological dioptrics. pprrpos, modum tenens, and &ty, oculus). Suchan eye we term emmetropic. This name expresses perfectly what we mean. The eye cannot becalled a normal eye, for it may very easily be abnormal or morbid,and nevertheless it may he emmetropic. Neither is the expressionnormally constructed eye quite correct, for the structure of an emme-tropic eye may in many respects be abnormal, and emmetropiamay exist with difference of structure. Hence the word emmetropiaappears alone to express with
. On the anomalies of accommodation and refraction of the eye, witha preliminary essay on physiological dioptrics. pprrpos, modum tenens, and &ty, oculus). Suchan eye we term emmetropic. This name expresses perfectly what we mean. The eye cannot becalled a normal eye, for it may very easily be abnormal or morbid,and nevertheless it may he emmetropic. Neither is the expressionnormally constructed eye quite correct, for the structure of an emme-tropic eye may in many respects be abnormal, and emmetropiamay exist with difference of structure. Hence the word emmetropiaappears alone to express with precision and accuracy the conditionalluded to. Emmetropia then is met with, when the principal focus of themedia of the eye at rest falls on the anterior surface of the most ex-ternal layer of the retina (compare Fig. 51). This is thesimplest definition. The eye may deviate from the emmetropic condition in two re-spects : the principal focus 0 of the eye at rest may fall in front qf 6 82 DEFECTS OF REFRACTION AND ACCOMMODATION. (Fig. 52) or behind (Fig. 53) the most external layer of the retina Eis. Fiff. 53.
Size: 2307px × 1083px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, bookidonanomalieso, bookyear1864
