DEPARTMENT OF SURGERY. 
131 
should never be used in plastic iritis ; so with many other condi¬ 
tions. Before resorting to such surgical interference a proper 
diagnosis must always be made, and to accomplish this it is 
necessary to make a thorough examination of the eye. 
Examination of a Horse's Eye .—The conjunctiva and ex¬ 
ternal surface of the eyeball can be examined by parting the 
eyelids with the thumb and forefinger. {Fig. 45.) When 
standing in front of the horse, the right hand is used to examine 
the right eye (Fig 45-B), but when the examiner stands to the 
side of the horse’s head, the right hand is used to examine the 
left eye and the left hand for the right eye {Fig. 45—A). The 
membrana nictitans is brought to view by pressure applied to 
the eyeball with the forefinger and thumb. 
The conjunctiva of the eyelid can be thoroughly examined 
by catching the eyelashes with thumb and forefinger of one or 
both hands and inverting the eyelid over a lead pencil, ther¬ 
mometer case or some other object of that shape. If the eye or 
its appendages are very sensitive, a little cocaine may be in¬ 
jected into the eye between the ball and the lids before making 
the examination. 
To examine the antro-internal part of the eye, the patient 
should be taken to a dark room or stall and the eye illuminated 
with a candle placed in front of it. A thorough examination 
necessitates the use of mydriatics, administered a few hours prior 
to the examination. 
A normal eye will reflect images of the candle light; one 
large and two small ones. The first large image of the light is 
observed in its normal position, and is reflected by the cornea ; 
the second is smaller, in an upright position as the first, and is 
reflected by the anterior part of the lens ; the third is a small 
inverted image of the flame reflected from the posterior part of 
the lens. When the eye is normal all the images are well de¬ 
fined ; but when either of them presents an indefinite outline it 
is an indication that there is some abnormal condition of the 
anterior part of the eye. When the first image presents an in¬ 
definite outline, the trouble is in the cornea ; when the second 
one is hazy or indefinite the lesion is in the aqueous humor or 
the anterior part of the lens ; and when the third is indistinct 
it is in the lens. {Fig. 46.) 
The ophthalmoscope is an instrument that should be more 
generally used by veterinarians. The belief that it is an instru¬ 
ment difficult to use to a good advantage is erroneous ; an hour’s 
instruction will enable any veterinarian to acquire good com- 
