. Anatomy, descriptive and applied. Anatomy. THE CRYSTALLINE LENS 1111 ment varying from the slightest degree to the separation of the whole iris from its ciliary con- nection. The Argyll-Robertson pupil shows no reaction to light, but retains reaction to accommodation and vision remains good. The retina, with the exception of its pigment layer, and its vessels is perfectly transparent, and is invisible when examined by the ophthalmoscope, so that its diseased conditions are rec- ognized by its loss of transparency. In rctiniii.'i, for instance, there is more or less dense and extensive opacit
. Anatomy, descriptive and applied. Anatomy. THE CRYSTALLINE LENS 1111 ment varying from the slightest degree to the separation of the whole iris from its ciliary con- nection. The Argyll-Robertson pupil shows no reaction to light, but retains reaction to accommodation and vision remains good. The retina, with the exception of its pigment layer, and its vessels is perfectly transparent, and is invisible when examined by the ophthalmoscope, so that its diseased conditions are rec- ognized by its loss of transparency. In rctiniii.'i, for instance, there is more or less dense and extensive opacity of its structure, and not infrequently extravasations of blood info its sub- stance. Hemorrhages may also take place into the retina from rupture of a bloodvessel without inflammation. In optic neuritis, papillitis, or choked .disk, the ophthalmoscope shows increase in vascularity, and swelling and opacity of the nerve, which extend beyond the disk margins. Optic atrophy is apt to follow. (Fig. shows a normal optic disk.) The retina may become displaced from effusion of serum between it and the choroid or by blows on the eyeball, or may occur without apparent cause in progressive mijopia, and in this case the ophthalmoscope shows an opac|ue, tremulous cloud. Glioma, a form of sarcoma, and essentially a disease of early life, is occasionally met with in connection with the retina. The lens has no bloodvessels, nerves, or connective tissue in its structure, and therefore is not subject to those morbid changes to which tissues containing these structures are liable. It does, however, present certain morbid or abnormal conditions of various kinds. Thus, variations in shape, absence of the whole or a part of the lens, and displacements are among its congenital defects. Opacities may occur from injury, senile changes, malnutrition, or errors in growth or development. An opacity of the capsule, of the lens, or of both, is known as a cataract. Senile changes may take place in th
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
