The exact cause is not actually known but intraocular pressure plays the largest risk factor. Interestingly some people with higher than normal eye pressures never develop glaucoma. While some people with normal/average eye pressure develop glaucoma. This type of glaucoma is called “low or normal tension glaucoma” and may involve other factors such as poor blood flow to the optic nerve. Other scientists have proposed that the structural components of the optic nerve may be weak where the optic nerve joins the eye itself. One thing is for sure, no matter what the mechanism of a person’s glaucoma, glaucoma runs in families. Therefore family members of someone with the diagnosis of glaucoma should have an eye exam to screen for glaucoma. The genetics are multivariable but certain genes have already been found.