t structure
to lie behind the outer surface of the sclera. Atrophy and cystic
degeneration of the nerve trunk follows destruction of retinal neurons
and cupping of the disc. Neuroglia remains in part. Connective tissue
elements increase in the optic nerve as the nerve fibers disappear.

_Glaucomatous Ring._ The development of the pale circle which surrounds
the disc, particularly in glaucomatous eyes, is due to a very slight
recession of the pigment layer of the retina and of the margin of the
chorioid at this point with some atrophy, apparently consequent on the
beginning retraction of the lamina cribrosa and slightly increased
pressure of the nerve fiber layer on the underlying tissues at the
margin of the disc. This permits the sclera to show through a very
little at this part. In some eyes in which there is a beginning
sclero-chorioiditis posterior, the condition is very similar to that
presented by the glaucomatous ring.

_Field of Vision._ The two pathological processes that operate to
destroy the function of the retina suffice to produce scotomata in the
field of vision of varying shapes. The typical glaucomatous field in the
acute cases shows a defect most pronounced to the nasal side. As has
been shown by Bjeraum, the blind spot corresponding with the optic disc
is enlarged in glaucoma, a relative scotoma often connecting it with the
blind nasal portion of the field either above or below the horizontal
meridian (Straub). The field in a simple glaucoma is apt to approach
concentric limitation; namely, more like the field in simple atrophy.
This is consistent with the fact that simple glaucoma in many cases
possesses the characteristics of glaucoma plus atrophy of the optic
nerve.

_Vitreous._ During the acute attack, the vitreous may become slightly
turbid by transudation of serum from the vessel of the ciliary body and
the chorioid and may become filled with fibrin. In some chronic cases
in which absolute glaucoma is reached the development of small blood
vessels in convoluted loops springing from the vessels of the discs has
been observed. Any process that increases the volume of the contents of
the vitreous chamber, as hemorrhage, neoplasm, profuse serous or plastic
exudation, may by pushing iris and lens forward produce an attack of
acute glaucoma.

_Buphthalmos._ Reis (Graefe's Arch. f. Ophth. V. LX. 1905) states that
there is always obliteration of the anterior scleral venous channels
(Schlemm's canal