There are two main types of glaucoma, primary and secondary. In primary glaucoma, the cause of the increase in pressure is due to a problem in the drainage angle. It is frequently an inherited problem. Beagles, Basset Hounds, and Cocker Spaniels are prone to this type of glaucoma. In secondary glaucoma the pressure is too high because something else is wrong in the eye, such as a lens luxation, bleeding, inflammation, or tumor.
Aqueous humor made in the ciliary body flows through the pupil into the anterior chamber.
Aqueous then drains into the bloodstream through the iridocorneal angle. Medical treatment consists of a number of different drugs used in combination. Some are given by mouth and effect the whole body, while others are put directly into the eye and have a local effect. The drugs that work when the problem is first diagnosed may not work forever. Therefore, the intraocular pressure needs to be monitored on a regular basis so that the medication regimen can be altered to fit the needs of the patient.