644: OPHTHALMIA the arms are very fragile ; the common name of the genus ophiura is sand star, from their habit of hiding in the sand. The viscera are confined to the central circular disk ; the arms are not excavated in grooves below for the protrusion of ambulacral tubes ; they swim and creep with facility by means of the spines or the arms. In ophioeoma the arms are so readily detached, at the will of the animal, that Serpent Star (Ophiopholis). they are called " brittle stars." In the group of euryalcB the arms are much branched ; the genus astrophyton of the North American coast has so great a number of terminal subdivisions, like snaky hairs, that it has been called Medu- sa's head ; it is also called fisherman's basket, from occasionally having, when caught in deep water, fish and other animals embraced in the Astrophyton Agassizii. numerous flexible rays. According to T. Ly- man, there are more than a dozen species of ophiurans on the coast of the United States. OPHTHALMIA (Gr. 600aA/'a, from bQdafyoe, an eye), inflammation of the eyes. Under the head of ophthalmia may be included inflamma- tion of all the various structures that enter into the formation of the eye ; we shall here however confine ourselves to the inflammation of the external and visible tissues. Inflamma- tion of the white of the eye assumes a vari- ety of forms, dependent partly on the special character of the inflammation and partly on the constitutional peculiarities of the patient. 1. Catarrhal Ophthalmia. Here the eyes are bloodshot, the redness being produced by in- jection of the network of vessels which covers the white of the eye, and early in the disease is most marked where the conjunctiva is re- flected from the lids, while it gradually lessens as we approach the cornea. The lids are swol- len, and sometimes the upper lid overlaps a little the lower one. The patient complains of a feeling as if there were sand in the eye, while there is a good deal of smarting and itch- ing at the angles of the eyelids and along their free margins. There is at first lachrymation, which is soon followed by the secretion of a thin muco-purulent discharge which accumu- lates at the corners of the eye, and which with an increased secretion of the Meibomian glands glues the eyelids together during sleep. The disease may be brought on by irritation or injury of the conjunctiva, though atmospheric influences are its commonest cause. It is or- dinarily mild and manageable, but when severe or badly treated it may produce ulceration of the cornea or leave the lids thickened and gran- ular. In all cases of disease of the eye, abso- lute rest of the organ should be enjoined, and it should be protected from strong light and heat. In mild cases of catarrhal ophthalmia, rest, a brisk purgative, and the occasional ap- plication of tepid water to the eye, are often all that is necessary. If the inflammation does not subside in the course of one or two days, a weak solution of nitrate of silver (gr. ii.-vi. aq. i.) may be dropped into the eye once a day, and the eye may be bathed several times a day with a dilute solution of alum or of bi- chloride of mercury ; while at night the edges of the lids may be smeared with dilute cit- rine or red precipitate ointment. In the severe form, bloodletting, either general, or more com- monly by means of cupping glasses to the tem- ples or of leeches, may be required. When the palpebral conjunctiva is congested and thick- ened, it may be scarified, and after the active inflammation has subsided it may be brushed over with strong nitrate of silver ointment or with undiluted vinum opii. 2. Egyptian Oph- thalmia Purulent Ophthalmia. This disease has probably existed at various places and va- rious times, but the attention of the public was first strongly directed to it during the wars of Napoleon, when the British army returning from the expedition to Egypt brought the dis- ease with them, and communicated it to other troops with whom they came in contact. The milder cases of purulent ophthalmia differ but little from the severer cases of the catarrhal form of the complaint ; there is however even in these cases a very marked tendency to a granular condition of the lids. "When the lids are everted they appear velvety, " the enlarged
