DISEASES OF THE RETINA AND CHORIOID 129 



veins, and, in many cases, numerous hemorrhages. 

 White spots appear scattered about the fundus, due to 

 the presence of exudates. These exudates often pass 

 into the vitreous, causing opacities in this substance. 

 The vision is reduced according to the site and degree 

 of the inflammation, which is general, though it may be 

 localized. 



The appearance by ophthalmoscopic examination 

 often depends upon the cause, though in many cases 

 the cause is not easily found. Among the various causes 

 are Bright's disease, diabetes, syphiHs, diseases of the 

 vascular system, and diseases of the blood. 



The characteristic early appearance in Bright's 

 disease is a radiation of white spots about the macula 

 with occasional hemorrhages, and larger exudates in 

 various portions of the retina, together with other lesions 

 above described. This form of retinitis frequently^ 

 occurs in the bitch during the stage of pregnancy. 



The only way to determine the cause of retinitis is 

 to give the animal a thorough physical examination, in- 

 cluding a chemic and microscopic examination of the 

 urine and blood. 



Atrophy of the retina often occurs as a result of a long 

 period of inflammation, or the reduction of its nutrition 



There is one particular condition which is not infrequent and should 

 not be mistaken as pathologic; this is a series of medullated fibers which 

 appear like a white flame extending from the optic nerve upward and 

 downward, or in one direction only. In such a case the general symptoms 

 of retinitis are absent. 

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