Summary

Secondary Open Angle Glaucoma is a glaucoma where the angle between iris and the cornea is in an ‘open’ configuration, and occurs as a result of another medical condition or trauma.

Classification

We can classify causes of secondary open angle glaucoma into three categories based on where the aqueous outflow obstruction is.

Pre-trabecular

Aqueous outflow is blocked by a membrane covering the trabecular meshwork. For example, fibrovascular tissue, such as in neovascular glaucoma, endothelial cell proliferation or epithelial cell proliferation.

Trabecular

This is where clogging of the meshwork itself prevents aqueous outflow. Examples, and the various materials that block the meshwork, are listed below:

• Pigmentary glaucoma – pigment particles
• Red cell glaucoma – red bloof cells
• Ghost cell glaucoma – degenerate red cells
• Phacolytic glaucoma – macrophages and lens proteins
• Hypertensive uveitis – proteins
• Psuedoexfoliative glaucoma – pseudoexfoliative material
• Trabecular glaucoma can also be caused by oedema (trabeculitis) or by any scarring (e.g. after post-traumatic angle recession)