Editing Glaucoma (section)

===Primary glaucoma and its variants===
Primary glaucoma (H40.1-H40.2) includes primary open-angle glaucoma (chronic open-angle, chronic simple, glaucoma simplex) which can be high-tension or low-tension, and primary angle closure glaucoma (primary closed-angle, narrow-angle, pupil-block, acute congestive), which can manifest as acute, chronic, intermittent, or superimposed on chronic open-angle closure glaucoma (also called "combined mechanism" glaucoma).

Other variants of primary glaucoma include:
*[[Pigment dispersion syndrome|Pigmentary glaucoma]]
*[[Exfoliation glaucoma]], also known as pseudoexfoliative glaucoma or glaucoma capsulare
*[[Primary juvenile glaucoma]]

'''Primary angle closure glaucoma''' is caused by contact between the iris and trabecular meshwork, which in turn obstructs outflow of the aqueous humor from the eye. This contact between iris and trabecular meshwork (TM) may gradually damage the function of the meshwork until it fails to keep pace with aqueous production, and the pressure rises. In over half of all cases, prolonged contact between iris and TM causes the formation of synechiae (effectively "scars").

These cause permanent obstruction of aqueous outflow. In some cases, pressure may rapidly build up in the eye, causing pain and redness (symptomatic, or so-called "acute"-angle closure). In this situation, the vision may become blurred, and halos may be seen around bright lights. Accompanying symptoms may include a headache and vomiting.

Diagnosis is made from physical signs and symptoms - pupils mid-dilated and unresponsive to light, cornea edematous (cloudy), reduced vision, redness, and pain. However, the majority of cases are asymptomatic. Prior to the very severe loss of vision, these cases can only be identified by examination, generally by an eye-care professional.