Filtration Angle ; Glaucoma 91 



lattice- work, ligamentum pectinatum (pectinatim, adv., like the teeth of 

 a comb], which occupies the narrow peripheral part of the anterior 

 chamber, between the cornea and the root of the iris. This important 

 crevice is, therefore, called the filtration angle. It becomes blocked 

 when, as the result of an excessive secretion of the vitreous, the ciliary 

 processes are thrust against the iris, and the iris is thrust against the 

 cornea. And its connection with the posterior chamber is, of course, 

 completely shut out when, as the result of iritis, the pupillary border, of 

 the iris is glued to the front of the capsule of the lens or to the posterior 

 surface of the cornea. 



Whenever the tideway from the vitreous and the posterior chamber 

 into the anterior chamber is 

 blocked, the fluids collect behind 

 the iris and push it towards the 

 cornea, increase of the ocular 

 tension promptly taking place. 



Thus, the tension may be in- 

 creased in the case of excessive 

 secretion from the ciliary pro- 

 cesses into the vitreous, and also 

 in that of a blockade of the filtra- 

 tion-angle. It is this increased 

 tension of theeye-ball which is 

 the essential feature of glau- 

 coma (yAavKos-, bluish-green). 



Symptoms of glaucoma, in 

 addition to that of hardness of 

 the eye-ball : Pain, on account 

 of the compression of the ciliary 

 nerves within the rigid sclerotic ; 

 advancement of the iris, as 

 already explained, and errors of 

 refraction, on account of the 

 grave interference with accom- 

 modation. 



Then, if the media are clear 

 enough for the ophthalmoscope, 

 the veins at the fundus are seen 

 to be full and pulsating, because 

 the tension of the sclerotic prevents their emptying themselves ; and 

 the arteria centralis is found throbbing in its endeavour to force its con- 

 tents through the engorged capillaries. And the backward pressure 

 of the vitreous causes a manifest depression or even a cupping of the 

 optic disc, but in an acute case the general destruction of the tissues 

 may render this invisible. Atropine must not be used, as this causes 

 the ris still farther to encroach on the filtration-angle. 



Iritis ; annular posterior synechia, aqueous 

 locked in behind iris, which, thus pushed 

 forwards, blocks filtration-angle and deter- 

 mines glaucoma. (PRIESTLEY SMITH.) 



