Closed angle glaucoma is less common than open angle glaucoma, but the damage to the optic nerve can be faster and more severe. With closed angle glaucoma, the iris blocks the drainage canals when the pupil enlarges. in dim illumination or as a result of stress or medications. When the drainage gets blocked, the pressure can rise quickly and the patient may notice symptoms such as headaches, eye pain, rainbows around lights at night, blurred vision, and nausea. As a note of importance,there is a subacute (slower) form of closed angle glaucoma where the symptoms are not as intense and may go unchecked; patients sometimes mistake their symptoms for those of migraines. Closed angles or narrow angles can easily be diagnosed with a simple in office test and could save your vision.