The student's guide to diseases of the eye . oryligament, so that theiris, having lost its sup-port, will shake aboutwith every movement(tremulous iris). Suchlesions are likely to beobscured for a time bybleeding into the ante-rior chamber and intothe vitreous. The lens often becomes opaque afterwards (p. 157). Detachmentof the retina is often found after severe blows, whichhave caused haemorrhage into the vitreous.—Blows onthe front of the eye may cause rupture of the choroid, orhcemorrhage from choroidal or retinal vessels. Thesechanges are found at the central part of the fundus,often almos
The student's guide to diseases of the eye . oryligament, so that theiris, having lost its sup-port, will shake aboutwith every movement(tremulous iris). Suchlesions are likely to beobscured for a time bybleeding into the ante-rior chamber and intothe vitreous. The lens often becomes opaque afterwards (p. 157). Detachmentof the retina is often found after severe blows, whichhave caused haemorrhage into the vitreous.—Blows onthe front of the eye may cause rupture of the choroid, orhcemorrhage from choroidal or retinal vessels. Thesechanges are found at the central part of the fundus,often almost exactly at the yellow spot, thus causingmuch damage to sight. The rents in the choroidappear, after the blood has cleared up, as lines ornarrow bands of atrophy bordered by pigment, andoften slightly curved towards the disc (Fig. 69).Haemorrhages from the choroidal vessels withoutrupture of the choroid, usually leave some residualpigment after absorption.—Paralysis of the iris andciliary muscle, with partial and often irregular, dila-. FiG. 56.—Separation of iris fol-lowing a blow (after Lawson). 140 INJURIES OF THE EYEBALL tation of the pupil are sometimes the sole resultsof a blow on the eye. The defect of sight can beremedied by a convex lens. When uncomplicatedthese symptoms are seldom permanent. (For Trau-matic Iritis, see p. 121.) Great defect of sight following a blow, and neitherremedied by glasses nor accounted for by blood inthe anterior chamber, will generally mean copioushaemorrhage into the vitreous, with or without theother changes just mentioned in the retina and cho-roid. The red blood may sometimes be seen by focallight, but often its presence can only be inferredfrom the opaque state of the vitreous. Probably inmost of these cases the blood comes from the largeveins of the ciliary body, but sometimes from thevessels of the choroid or retina. There may be noexternal ecchymosis. The tension of the globe is tobe noted ; it is not often increased unless in
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