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CATARACT 517 



CATARACT. 



This is an opacity of the lens or its capsule. 



NOMENCLATURE. 



If the opacity commences about the centre of the lens it is a nuclear 

 cataract, if about the periphery il is a cortical cataract. The former 

 tend to develop in old age, the latter during middle life. 



The hard variety are senile, common after the forty-fifth year and 

 can be extracted, but the soft may occur from childbirth to the thirtieth 

 year and require needling, &c. All cataracts occurring under the 

 thirtieth year are soft. 



Cataracts are primary when independent of any other ocular 

 condition. 

 ,, ,, secondary when other ocular disturbances are 



present. 



lenticular when in the substance of the lens. 

 capsular when affecting the capsule. 

 capsulo-lenticular when involving both. 

 ,, ,, stationary when they remain incomplete. 



,, ,, progressive when they spread and tend to affect the 



whole lens. 

 ,, ,, congenital when they are due to faulty intrauterine 



development or inflammation. 



These include the anterior and posterior polar, 

 lamellar and sometimes the complete cataract. 

 ,, ,, traumatic when the capsule is pierced or ruptured by 



a foreign body or bv a simple concussion allowing 

 the lens to absorb the aqueous humour. 

 We shall follow a classification of May and Worth and deal with 

 each seriatim. 



A. Stationary Cataracts. 

 (i) Anterior polar. 



(2) Posterior polar. 



(3) Lamellar. 



(4) Uncommon forms. 



B. Progressive Cataracts. 



(i) Senile, cortical and nuclear. 



(2) Congenital, juvenile. 



(3) Traumatic. 



(4) Catarrhal eye complications. 



(5) After cataract. 



