Retro-Bidbar Optic Neuritis. 441 



pupil may be at first strongly contracted and later freely dilated. 

 Treattnent is usually of little avail and does not differ mater- 

 ially from that adopted in retinitis. In tumor of the orbit press- 

 ing on the optic nerve it may sometimes be reached through the 

 temporal fossa, but usuall}' in all such cases enucleation of the 

 eyeball is demanded. 



RKTRO-BULBAR OPTIC NEURITIS. 



Definition. Neurites descendens and ascendens. Extension to bulb, 

 other eye, or brain. Causes : traumas, meningitis, infectious diseases, 

 toxins, lead, tobacco, etc. Symptoms : partial blindness : congestion of 

 papilla, exudates in adjacent retina. Treatment : eliminate poisons, lead, 

 toxins, correct precedent disease, saline laxatives, diuretics, potassium 

 iodide, cupping, local bleeding, counter-irritants. Hygiene. 



This is inflammation of the optic nerve commencing behind the 

 eyeball and only involving tlie papilla secondarily. Extension to 

 the papilla has been called neuritis descendens '\\\ contra-distinction 

 to neuritis ascendents in which the inflammation extends along the 

 nerve toward the brain. There is always a tendency to exten- 

 sion, it may be to the papilla and retina, it may be to the chiasma 

 and opposite eye, and it may be inward toward the ganglia and 

 choroid plexus. 



Causes. Apart from traumatic cau.ses, retro-bulbar neuritis in 

 the domestic animals has been mainly seen in connection with 

 constitutional or infectious diseases ; in the horse with petechial 

 fever (Peters), contagious pneumonia (Schindelkaj, meningitis 

 (Peters, Straub) and parotitis (Moller). It has also followed 

 meningitis in cattle (Nebelen). In man it has been traced to 

 lead, tobacco, alcohol and other poisons. 



Symptoms. At first the patient may seem partially blind with- 

 out apparent cause. Eater ophthalmoscopic examination reveals 

 congestion and swelling of the papilla, and congestion (especially 

 venous and capillary ) of the retinal vessels. The discolorations 

 in streaks and spots, from exudates and degenerations follow as 

 noticed under papillitis. It is difficult to distinguish between this 

 and papillitis during life. 



