Headache that can cause Blindness

The experience of 60 years old male

​He often had to work until midnight because of the time difference of the country where the company was trading with. Headache like the head was squeezed occurred accompanying with nausea. He didn’t take it seriously because the headache got better with over-the-counter headache medicine and the nausea got better if he threw up. A year after the headache started, he had a sty on his eye on the day he was going out for dinner with his friend. When his friend saw his eye, he told him to go see a doctor. His friend happened to be an oculist. As a result of the inspection, he had glaucoma (Though the sty on his eye was not related to glaucoma).
 
Glaucoma is a group of eye diseases which results in damage to the optic nerve that transmits visual information from the retina to the brain and vision loss. Vision loss from glaucoma, once it has occurred, is permanent.
 
There are a few types of glaucoma. In his case, it was closed-angle glaucoma which can present gradually or suddenly. The sudden presentation may involve severe eye pain, blurred vision, mid-dilated pupil, redness of the eye, and nausea.

In the eye, there is flow of fluid to deliver nutrition or to control pressure within the eye. Because the exit of the fluid becomes narrow or gets clogged, the pressure within the eye increases. In the worst case, there is a possibility of blindness due to the damage of the optic nerve. After he had treatment, the headache and nausea disappeared.
 
Why do headache and nausea occur with glaucoma?
 
It is thought that increased pressure within the eye stimulates the nerves around the eye. The stimulation is transmitted through the trigeminal nerve and the autonomic nerves is stimulated, causing headache and nausea.
 
Other eye diseases accompanying with headache: optic neuritis, uveitis, Scintillating scotoma (visual migraine)