SYSTEMATIC EXAMINATION OF THE EYE 3 1 



cates a reflex contraction from the presence of a foreign 

 body or corneal ulcer, iritis, or the use of a myotic. 

 Paralysis of the sympathetic causes a small pupil in 

 both eyes. The pupils should be regular in shape. 

 If irregular, iritis is usually the cause. If the pupil is 

 not clear, look for a cataract, exudates in the chambers, 

 or a turbidity of the vitreous. 



- The iris should be clear and lustrous. Both irides 

 should be alike in this respect, though a difference in 

 the amount of pigment exists in many cases. If the 

 iris has lost its brilliancy and has changed its color 

 somewhat, an iritis may exist. A tremulous iris is the 

 result of loss of support, which is due to displacement 

 of the lens, absorption, or previous extraction of the 

 same. The iris is subject to cysts, tubercular growths, 

 etc. 



The normal lens is diflicult to see because of its trans- 

 parency; consequently, the pupil should be perfectly 

 clear normally, so that light reflected through the 

 pupil from the ophthalmoscopic mirror will show a red 

 reflex, otherwise there is some opacity of the interven- 

 ing media. Any opacity of the lens can readily be seen 

 by obHque illumination or by the aid of a strong lens 

 with the ophthalmoscope. A lens of 10 diopters will 

 disclose floating bodies in the vitreous. A smaU opacity 

 posterior to the lens center will move in the opposite 

 direction to the movement of the eye. A complete 

 cataract can be seen filling the whole pupillary space. 



