Why the angle narrows
The drainage angle is the space between the iris and the cornea. In a small, farsighted eye it is crowded from the start, and as the natural lens thickens with age it pushes the iris forward and narrows the angle further. If the iris bows against the meshwork, fluid cannot drain. Chronic closure scars the angle gradually. Acute closure happens when the pupil dilates in dim light, or with certain medications, and the iris bunches into an already narrow angle, blocking it completely; pressure can rise to several times normal within hours.
An acute attack: the symptoms
Sudden severe pain in and around one eye, often with a headache on that side; blurred vision; halos or rainbows around lights; a red eye; nausea and vomiting; and a hazy cornea with a mid-dilated pupil on examination. It usually begins in the evening or in dim light. This is an emergency: pressure must be lowered within hours to prevent permanent damage, with drops, tablets and then a laser iridotomy. Go to an emergency department or urgent eye clinic immediately; you can also call us at (855) 456-2253 during office hours.
Subacute and chronic closure
Many patients have milder intermittent episodes: aching, blur and halos in the evening that resolve on sleeping, when the pupil constricts. Others have gradual closure with no symptoms at all and present with established nerve damage like open-angle glaucoma. Gonioscopy at a glaucoma evaluation is how a narrow angle is found before either happens.
Prevention and treatment
- Laser peripheral iridotomy: a tiny opening in the iris made with a laser in the office, giving fluid a second route and preventing the iris from blocking the angle; it is the standard preventive treatment for narrow angles at risk of closure
- Lens extraction: removing the thickened natural lens, as in cataract surgery, deepens the angle permanently and is now often the preferred treatment for angle closure, particularly when a cataract is present
- Drops to lower pressure and constrict the pupil while definitive treatment is arranged, and long term if damage has occurred
- Avoidance of medications that dilate the pupil in untreated narrow angles, including some cold remedies and antidepressants, until the angle has been treated
After treatment
Once the angle is opened, the risk of acute closure is largely removed. Patients with established damage continue glaucoma treatment and monitoring as for open-angle disease. The other eye is usually treated too, because it shares the same anatomy.
Is this right for your eyes?
Nothing on this page is a diagnosis. Whether this is what is affecting your vision is decided by a full examination at one of our 4 offices: Pasadena, Huntington Beach, Woodland Hills and Beverly Hills.
About this content: This page was written with the assistance of AI tools and reviewed for medical accuracy by Dr. Bavand Youssefzadeh, DO. It is general information, not medical advice, and does not replace an eye examination. Individual results vary. Read our medical disclaimer.
