I have never heard of secondary glaucoma so I had to look it up.
- Secondary glaucoma. . ."can occur as the result of an eye injury, inflammation, tumor or in advanced cases of cataract or diabetes. It can also be caused by certain drugs such as steroids. This form of glaucoma may be mild or severe. The type of treatment will depend on whether it is open angle
or angle closure glaucoma
Open angle glaucoma
is the obstruction to the outflow of aqueous humor at the trabecular meshwork or Schlemm canal.
Acute angle closure glaucoma
is closure of the iridocorneal angle with a sudden rise in intraocular pressure which produces nerve pain and visual disturbances.
The loss of visual acuity is due to the pressure that is placed on the optic nerve. The elevated pressure blocks the flow of cytoplasm from the retina to the nerve fibers that are entering the brain. In so doing, nutrients for the nerve cells are unable to reach these neurons and they die. Pain is one of the symptoms as well as increased intraocular pressures over 20 mm Hg. (page 446-7, Pathophysiology: The Biologic Basis for Disease in Adults and Children
, third edition, by Kathryn L. McCance and Sue E. Heuther)