426 Veterinary Medicine. 



affecting the region of the ciliary circle and the sclero-comeal 

 line. 



Symptoms. The tension of the eyeball is excessive as ascer- 

 tained by pressure of the finger, or by the spring tonometer. 

 If the increase of tension has come on suddenly, the cornea is 

 somewhat cloudy, and less sensitive to the touch. If one eye 

 only is attacked the contrast between the two is very marked 

 and diagnostic. The anterior chamber is diminished in size by 

 the projection forward of the iris and lens. The iris is usually 

 contracted so as to show a dilated pupil reflecting a smoky, 

 grayish green or yellowish green hue. The iris is either irre- 

 sponsive to light or responds very slowly and imperfectly. 

 With the ophthalmoscope the most marked features are the 

 ' 'cupping' ' or depression of the optic disc by pressure, and the 

 pulsations in the retinal arteries. These pulsations are especially 

 easily seen at the margin of the depression which represents 

 the seat of the lamina cribrosa and the point of entrance of the 

 optic nerve. They are rendered even more manifest by pres- 

 sure on the eye. They are due to the prompt emptying of the 

 blood vessels by the intraocular pressure, so that these are only 

 momentarily filled at each cardiac systole. 



Ophthalmologists recognize three varieties of glaucoma : acute 

 inflammatory glaucoma, simple glaucoma without apparent 

 inflammation, and secondary glaucoma, the result of another 

 disease. 



Acute inflammatory glaucoma is the one condition in 

 which, in the absence of a midriatic, inflammation is associated 

 with dilated pupil. It is liable to occur in a series of attacks, 

 which increase in severity, hence its supposed identity with re- 

 current ophthalmia in the horse. The entire group of symptoms 

 have, however, been rarely or never seen in the horse. They 

 are distinctly more common in dogs. 



Simple glaucoma comes on more slowly, becomes chronic 

 and is to be recognized by the physical symptoms in the absence 

 of inflammation, notably by tension of the bulb, diminution of 

 the anterior chamber and cupping of the optic disc. 



Secondary glaucoma is the direct result of some other disease 

 of the eye : 



