CATARACT. 115 



Ccapsular and lenticular, or capsulo-lenticular. Capsular is 

 when tlie capsule is the seat of the cataract; lenticular is when 

 the crystalline lens is affected ; and when both the crystal- 

 line lens and its capsule are involved, it is known as a capsulo- 

 lenticular cataract. Cataract is occasionally noticed in the 

 young animal as soon as born, and is then known as congeni- 

 tal cataract. If cataract is well marked, it may be detected 

 without the slightest difficulty. If the whole lens is aff'ected, 

 the eye will lose the power of vision, after which atrophy of 

 the eyeball soon follow"s. The pupillary opening loses its 

 elliptical form, and becomes round and abnormally large. 



Symptoms. — As above stated, if the cataract be of good 

 size, it may easily be detected. If it be, on the contrary-, 

 small, its detection is in many cases a pretty difficult matter. 

 Where a small cataract exists, on examination, the eye is 

 noticed to be retracted, and the pupil, on sudden exposure 

 to light, is observed to contract to an unnatural degree. In 

 some cases the cataract may be imperceptible on account of 

 the minuteness of its size. In such a case, the animal is to 

 be placed in a darkened box, and the eje exa nined with the 

 aid of artificial light, as a candle, and, if necessary, an 

 ophthalmoscope. The use of the ophthalmoscope, however, 

 requires practice and expertness, and unless the practitioner 

 be possessed of both, the ophthalmoscope will be more of a 

 hindrance than an aid in the examination. At the same time 

 it should be borne in mind that in some cases the presence of 

 a very small cataract cannot be detected without the aid of 

 this instrument, as the catoptric test, while being nearly 

 always sufficient, will occasionally fail to reveal the pre- 

 sence of a very small cataract. After dilating the pupil with 

 belladonna or atropine, and placing the horse in a darkened 

 box, examine the eye by aid of candle-light. In many cases 

 the cataract will at once be seen. The person making the 

 examination should be careful to keep concealed any br.ght 



d>—2 



