Glaucoma CAN cause headaches.
More Info: The intraocular pressure (IOP) of glaucoma caused by fluid build-up in the eye can cause a headache. In some instances, migraine headaches are actually cases of glaucoma that have not been treated. The pressure build up in the eye can cause a headache that is felt in and around the eyes and forehead and can sometimes be severe enough as to cause nausea and vomiting.
Glaucoma Associated Headaches Research
Journal of Investigative Ophthalmology & Visual Science : In a case study published in the Journal of Investigative Ophthalmology & Visual Science, researchers investigated the incidence of headaches in those suffering from glaucoma and concluded that patients suffering from low-tension glaucoma seem more at risk for headache and migraine symptoms.
Phelps, Charles D., and James J. Corbett. "Migraine and Low-Tension Glaucoma." Investigative Ophthalmology & Visual Science 26.1 (1985): 1105-1108. Print.
Neurology: Twenty years following the above case study, researchers noted in a study published in the journal Neurology that patients suffering from subacute angle-closure glaucoma often sought medical attention for headaches leading to a misdiagnosis.
Shindler, KS, PS Sankar, NJ Volpe, and JR Piltz-Seymour. "Intermittent Headaches as the Presenting Sign of Subacute Angle-Closure Glaucoma." Neurology 13.65 (2005): 757-768. Print.
Headache: A similar study published in the journal Headache also concluded that patients suffering from subacute angle-closure glaucoma that do not have eye discomfort, often complain of headaches and are misdiagnosed.
Nesher, R, E Epstein, Y Stern, E Assia, and G Nesher.. "Headaches as the Main Presenting Symptom of Subacute Angle Closure Glaucoma." Headache 45.2 (2005): 172-176. Print.