CATARACT

From Agepedia

CATARACT. By this term two very different diseases are designated by some writers, viz. the true cataract^ and amaurosis, or gutta serena. By the first of these terms, in its most common signification, is understood opacity of the crystalline lens, or its capsule, or both. By the second is meant a disease of the retina, by which it is rendered unsusceptible of the action of light. In cataract, the lens becomes opaque, loses its transparency, and is no longer capable of transmitting the light. The causes of cataract are numerous. Inflammation may produce it. Sometimes it is ascribed to a state of the vessels of the part which prevents a proper nourishment of the lens or its capsule. It is produced by various diseases, such as gout, rheumatism, scrofula, and accompanies old age. Its earliest approach is marked by a loss of the natural color of the pupil; this becoming turbid, or slightly gray. Muscce volitantes accompany this period. The opacity is not, at first, over the whole crystalline, and, most frequently, first attacks the centre portion; this being turbid, and of a grayish color, while the surrounding portions remain transparent, and of the usual black color. While it exists in this degree only, the person can see in an oblique direction. The color of the pupil is various ; mostly grayishwhite or pearlcolored ; sometimes milkwhite, or of a yellowishgray; now and then of a grayishbrown, and even of a darkbrown or darkgray. The consistence of the lens differs in different cases, being either hard, and even horny, or very soft, as if dissolved.The treatment of cataract is by a surgical operation on the eye, and different operations have been tried and recom. mended. They all consist in removing the diseased lens from its situation opposite the transparent cornea. By one of these operations, the cataract is depressed, removed downwards, and kept from rising by the vitreous humor. This is called couching. Another operation is extraction, and consists in making an incision of the cornea, and of the capsule of the lens, by which, the lens may be brought forward, and through the cut in the cornea. The third operation is by absorption. This consists in wounding the capsule, breaking down the crystalline, and bringing the fragments into the anterior chamber of the eye, where they are exposed to the action of the aqueous humor, and are, at length, absorbed. This last operation has the name keratonyxis applied to it. The choice of the operation is determined by. the character of the cataract. After the operation, the patient is to be kept from the light, and from all means of irritation. Such medicines and such articles of food are to be prescribed as will most effectually prevent inflammation ; and should this occur, it must be treated by such means as are the most sure to restrain or overcome it.¦ Amaurosis is a disease of the optic nerve, and its continuation, the retina. Its causes are numerous. It may be occasioned by organic disease of the parts referred to, by mechanical pressure upon the nerve, by too powerful light, by longcontinued use of the eyes in too weak light, oy rapid transition from darkness to light, and, finally, by old age. Various other, and some more general, causes may produce amaurosis. Among these are wounds of the head, compression of the brain, fits of apoplexy, suppressed colds in the head, habitual inebriety, vomiting, coughing, sneezing, affections of the alimentary canal, and some of the neighboring viscerathe liver, for example. According to the activity of these various causes, the malady comes on suddenly or gradually. The patients are sometimes unable to bear the light, and, therefore, seek the darkness, where sparks and flames frequently appear to their eyes. Objects sometimes appear of different colors, or fluctuate, swim, and confuse themselves. At other times, the patients begin to squint, suffer a severe pain in the ball of the eye, and a straining above the eyebrows: finally, they begin to see as if through a crape or fog, and only in bright daylight can distinguish accurately: black flakes and specks appear to hover before their eyes. The greatest insensibility of the retina is often opposite the centre of the cornea; but ultimately the disease produces total blind ness, the pupil losing its motion, and hecoming permanently dilated. Deep in the eye a white speck is often visible, which is traversed by veins. According to the different causes, the malady is either easily cured or is incurable. Regard is especially to be had to them in the selection and use of remedies.