QUESTIONS AND ANSWERS 219 



What animals suffer from contagious ophthalmia? Give the diagnosis 

 and treatment of contagious ophthalmia. 

 Seen principally in cattle. Several cattle in the herd show 

 lachrymation, photophobia, mucopurulent discharge, swelling and 

 tenderness of the lids, fibrinopurulent exudate in the anterior cham- 

 ber. In some mild cases, only a conjunctivitis is seen. 



Treatment : Eyewash of boric acid solution (4 per cent.) to which 

 may be added 1 per cent, of atropine sulphate. Protect the eyes 

 from aU bright light. Segregate 'affected animals. 



Define cataract. Name the different forms of cataract and give the 

 diagnosis. 



A cataract is any pathological change in the lens or its capsule 

 which diminishes its transparency. 



Varieties: Congenital, senile, soft, hard, incipient, mature, pri- 

 mary, secondary, capsular, lenticular, stationary, progressive, 

 traumatic, etc. 



Diagnosis : History of previous attacks of periodic ophthalmia, 

 or simple ophthalmia ; atrophy of the globe ; dilate the pupil with 

 atropia and illuminate the depth of the eye with the ophthalmoscope 

 when opacities will be more readily detected. Hold a lighted candle 

 before the eye; in the normal eye, three images are reflected, one 

 from the cornea, one from the anterior capsule of the lens and one 

 from the posterior capsule. Any opacities in the lens will cause the 

 posterior image to become indistinct as it passes over that spot. 



What conditions may give rise to cataract? 



Impaired nutrition of lens, inflammation of the iris, choroid, 

 ciliary body and retina, periodic ophthalmia, diabetes, cell prolifera- 

 tion in the lens. 



Give the treatment of lachrymal fistula. 



Establish drainage through the lachrymal duct by forcing boric 

 acid solution through it from below upward under slight pressure. 

 Curette the fistulous opening and cauterize with silver nitrate. 



Describe an operation for enucleation of the eye. 



General anaesthesia is essential. Wash and disinfect the eye and 

 surrounding parts. Retract the lids ; make the incision through the 

 conjunctiva around the corneal margin and dissect back the con- 

 junctiva to the insertion of muscles. With small curved scissors 

 cut the muscles near their tendinous insertion. Then with strong 

 curved scissors, cut the optic nerve with one snip. The eye can 

 then be pried out. Check hemorrhage by packing the cavity with 

 aseptic gauze for a few hours. 



