422 DISEASES OF THE EYES 



distant from the corneal border and is pushed underneath the iris, 

 between it and the lens to the median line, until it is visible in the pupil. 

 When the needle has reached the inner or nasal border of the pupil, the 

 needle is pushed back against the lens and by steady pressure the lens 

 is dislocated from its supports and pushed backwards into the vitreous 

 humor. The lens must be held in position to endeavor to prevent its 

 return, but it is very apt at times to partially re-enter the pupillary 

 opening. 



DISEASES OF THE SCLEROTIC MEMBRANE, OF THE 



NERVOUS PORTION OF THE EYE, AND ALSO 



OF THE VITREOUS HUMOR. 



These diseases are generally not of any great importance compared 

 with the diseases before described, and therefore we will not go into 

 minute details. 



Anomalies of the Iris. — Of this organ there are two kinds: Persistent 

 papillary nieml)rane and iris coloboma. 



Persistent Papillary Membrane {Memhrana Papillaris Perservatrs) . — 

 The foetal papillary membrane extends in the shape of threads or strings 

 from the anterior surface of the iris to the capsule or over the pupil, or 

 their free ends may also float in the aqueous humor. Calve saw a young 

 dog, twelve months old, afTected like this and saw a similar condition in 

 the mother, and several of her offspring were blind from persistent 

 papillary membrane Moeller has seen a number of young dogs affected 

 in the same manner. 



Iris Coloboma. — This is a congenital split or division of the iris, 

 which is not at all rare. In the iris are found circular split-like openings 

 and there appear to be two and sometimes three pupils (Fig. 148). 

 There are also associated with this condition alterations in the ciliary 

 body of the choroid membrane. 



Inflammation of the Choroid. — This condition is very similar to 

 iritis, and the synii)toms are similar. Treatment consists in keeping 

 the animal in a dark place and solutions of cocaine to the eye. 



Inflammation of the Iris {Ii'itis). — This affection is very rare in the 

 dog and is apt to be associated with keratitis, cyclitis, or choroiditis. It 

 may also be due to extension of inflammatory processes and to trauma- 

 tisms, and is also said to be associated with rheumatoid conditions and 

 distemper. It may be recognized by contraction and difficulty of move- 

 ment of the iris, change in the color of the iris, fibrous accumulations in 

 the shape of a gray veil-like coating, and dulness of the fluid of the 

 anterior chamber, and slight dimness of the cornea. The cure for this 

 disease consists in complete rest, keeping the animal in a dark place, 



