<p><strong>Noun</strong></p><ul><li>Ophthalmology.</li><li>Abnormally high fluid pressure in the eye, most commonly caused either by blockage of the channel through which aqueous humor drains (open-angle glaucoma or chronic glaucoma) or by pressure of the iris against the lens, which traps the aqueous humor (angle-closure glaucoma or acute glaucoma).</li></ul>