Angle-Closure Glaucomaalso known as Closed-Angle Glaucoma, Narrow-Angle Glaucoma

Angle-closure glaucoma (ACG)—sometimes called closed-angle or narrow-angle glaucoma—occurs when the outer edge of the iris bows forward and blocks the eye’s drainage angle. Aqueous fluid can no longer leave through the trabecular meshwork, intra-ocular pressure (IOP) rises quickly, and the optic nerve is injured if treatment is delayed.[1] Although it accounts for only 10 % of glaucoma cases worldwide, ACG is responsible for a disproportionately high share of glaucoma-related blindness, especially in Asia and among older women with farsighted eyes.[2] Most eyes first pass through a primary angle-closure suspect (PACS) stage, progress to primary angle closure (PAC) when pressure or peripheral anterior synechiae develop, and finally to primary angle-closure glaucoma (PACG) once optic-nerve damage is documented. Timely laser peripheral iridotomy (LPI) or lens extraction can halt this sequence and preserve sight.

ACG spans a spectrum from silent to dramatic:

• Chronic (creeping) closure: The angle narrows gradually; many people feel fine but slowly lose side vision and need routine gonioscopy to catch changes.[3]
• Intermittent (sub-acute) attacks: Transient eye pain, halos, or blurred vision in dim light that clear when pupils constrict.
• Acute angle-closure crisis: Sudden severe ocular pain, red eye, headache, nausea/vomiting, mid-dilated unreactive pupil, and hazy cornea. IOP can exceed 50 mm Hg within hours and constitutes an ophthalmic emergency.[4]

Because the uninvolved eye shares the same anatomy, it is at high risk for a similar attack and should be prophylactically treated once the acute eye is stabilized.

The most common mechanism is pupillary block: aqueous humor trapped behind the iris pushes it forward, sealing the angle. Contributors and risk markers include:

• Shallow anterior chamber: Typical in hyperopic eyes and with age-related lens thickening.
• Age ≥ 50 years & female sex.
• Asian or Inuit ancestry—odds of PACG are 2- to 4-fold higher.[5]
• Positive family history; several HLA and PLEKHA7 variants have been linked to PACG.
• Plateau iris configuration or nanophthalmos.
• Medications that dilate the pupil (e.g., anticholinergics, adrenergic agents) or environments with dim illumination.

Knowing these factors helps clinicians decide who benefits from prophylactic laser treatment.

A comprehensive glaucoma work-up includes:

• Gonioscopy: Gold-standard assessment of the iridocorneal angle. Any trabecular meshwork not visible for >180° indicates narrow or closed angle.
• Anterior-segment OCT (AS-OCT) or ultrasound biomicroscopy to quantify angle opening distance and identify plateau iris.[6]
• Tonometry: Elevated IOP suggests progression from suspect to PAC or PACG.
• Optic-nerve evaluation & visual-field testing: Detect glaucomatous damage.
• Van Herick or pen-light test: Quick chair-side screening but inadequate as a stand-alone method.

Documenting angle anatomy on the day of diagnosis guides urgent versus elective intervention.

Acute attack (IOP crisis)

1. Topical beta-blocker, alpha-agonist, and pilocarpine every 15 min plus oral/IV acetazolamide to lower IOP.
2. Once corneal edema clears, perform laser peripheral iridotomy (LPI) to re-establish aqueous flow between chambers.[7]

Chronic or fellow-eye management

• Prophylactic LPI—reduces the 5-year conversion to PACG by ~75 % in high-risk eyes.
• Early cataract extraction / clear-lens exchange: Permanently deepens the angle and increasingly rivals LPI as first-line therapy in PACG with visually significant lens changes.[8]
• Trabeculectomy or glaucoma drainage device for eyes with residual high IOP after LPI and lens surgery.

You can protect your vision by:

• Routine dilated exams with gonioscopy every 1–2 years—or sooner if you have hyperopia or Asian ancestry.
• Recognizing early symptoms (halos, brow ache in dim lighting) and seeking same-day care.
• Medication adherence: Use prescribed drops exactly as directed.
• Medication review: Tell other doctors you have narrow angles before starting decongestants or certain psychiatric drugs.
• Healthy habits: Manage blood pressure, diabetes, and stay hydrated to support optic-nerve health.[9]

Most people maintain excellent vision when angle closure is detected and treated promptly.

Highlights from recent studies:

• LiGHT-ACG trial: Early LPI plus lens extraction produced better pressure control than LPI alone in symptomatic Asian eyes.
• Sustained-release bimatoprost-ring and intracameral implants are being tested to reduce drop burden after LPI.
• AI algorithms using AS-OCT images now predict which PACS eyes will progress to PAC within 18 months, enabling timely prophylaxis.
• Selective laser iridoplasty (SLIP) supplements LPI in plateau-iris syndrome and is under investigation as a primary procedure.
• Gene-therapy neuroprotection (AAV-delivered BDNF) slowed retinal-ganglion-cell death in PACG animal models.[10]

Who to see: Anyone with hyperopia, Asian ancestry, or a family history should have at least one lifelong baseline gonioscopy. If you develop acute eye pain, blurred vision, or halos, go to the nearest emergency department or on-call ophthalmologist immediately.

How to schedule: Ask for an urgent glaucoma referral; many practices reserve same-day or next-day slots for suspected angle closure. Tele-triage can help determine if an emergency visit is needed.

After evaluation and laser, keep follow-up appointments, use prescribed drops, and discuss early lens surgery if recommended. Our Kerbside platform can connect you with board-certified glaucoma specialists for second opinions and long-term care.