Glaucoma means increased pressure in the eye (intraocular pressure); there are two main types of disease. The most common is Open-Angle (aka Wide-Angle), which doesn’t cause a headache, has no symptoms, but can cause blindness. The much less common is Closed-Angle (aka Narrow-Angle), which causes a severe headache.
Headache occurs in Acute Closed-Angle Glaucoma when the pressure in one eye suddenly shoots up enormously. There’s a terrible pain behind the eye (patients often say “headache”), vomiting, the eye looks red and cloudy, vision is blurred. Unless surgery gets performed within 1-2 days, there’ll be permanent loss of vision.
Diagnosis is easy as long as we think about the eye. But it’s not uncommon for a patient to say they have “headache” instead of “eye pain.” Then the vomiting has led some clinicians to mistakenly call it a “migraine,” with disastrous results
We send such a person right to an ER. But it’s important to call first and make sure they have an ophthalmologist on-call. Many smaller ones don’t.
Acute Closed-Angle Glaucoma occurs mostly in Asian people. It’s very different from Chronic Open-Angle Glaucoma (a.k.a. “wide-angle”), which is much more common, including among Whites & Blacks.
Open-Angle Glaucoma has no symptoms; it also causes blindness, but very slowly over the years. The pressure damages nerves in the eye one by one, until the person goes permanently blind without realizing it. It’s as if a TV screen lost a pixel a day — in 10-20 years there’d be no picture left before you even realized it. Open-Angle Glaucoma can be diagnosed by routine exams by ophthalmologists or optometrists, who can measure pressure in the eye. It’s treated with special eye drops, and occasionally requires surgery.