Vision disturbances caused by glaucoma occur secondary to what condition?

The vision disturbances caused by glaucoma primarily result from damage to the optic nerve. In glaucoma, typically, there is an increase in intraocular pressure that can lead to this damage. As the optic nerve deteriorates, signals from the eye to the brain are disrupted, causing vision problems.

While increased intraocular pressure is a common precursor to glaucoma, the immediate cause of the vision disturbances is the effect on the optic nerve itself. Proper functioning of the optic nerve is crucial for clear visual transmission, and once it's compromised, the individual begins to experience vision loss.

The other options, such as lack of blood circulation to the eye and cataract formation, do not directly cause the optic nerve damage that leads to the characteristic vision disturbances seen in glaucoma. These conditions affect vision but through different mechanisms and do not specifically relate to the pathology of glaucoma.