Compare conditions

Put any two — or three — conditions side by side, adult or pediatric, to spot the look-alike differences fast, row by row.

Angle-Closure Glaucoma (Closed-Angle)

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In one line

·The drain inside your eye suddenly slams shut, pressure shoots sky-high in minutes, and the nerve that carries pictures to your brain can die within hours.

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Normal physiology

·Your eye constantly makes a clear, watery fluid called aqueous humor in a ring of tissue (the ciliary body) that sits just behind your iris. That fluid flows forward through the pupil, circles around the front of the eye to feed the lens and cornea with nutrients and oxygen, and then drains out through a spongy mesh (the trabecular meshwork) tucked into the drainage angle — the corner where your iris meets the cornea. From there it empties into a tiny canal (Schlemm's canal) and flows into small veins, like water leaving a sink. The balance between how much fluid is made and how much drains out keeps the pressure inside your eye steady and safe.

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What goes wrong

·Your iris suddenly moves forward or gets pushed hard against the drainage angle, slamming the exit shut. Fluid keeps being made at the normal rate but cannot leave, so pressure inside the eyeball climbs fast — like covering the drain in a sink while the tap is still running full blast.

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Hallmark signs

·Sudden, severe eye pain
·Blurry vision or sudden vision loss
·Seeing halos or rainbow rings around lights
·Red eye
·Headache (often on the same side as the affected eye)
·Nausea and vomiting
·Hard, firm eyeball when gently touched
·Pupil that is mid-sized and does not respond to light

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Red flags · escalate now

·Sudden severe eye pain with vision loss (permanent blindness can happen within hours if pressure is not brought down)
·Headache with nausea and vomiting along with eye redness (not just a stomach bug—this triad means possible angle closure)
·Eye feels rock-hard to gentle touch through the eyelid (sign of dangerously high pressure)
·Pupil is mid-sized, oval, and does not shrink in bright light (shows the iris sphincter muscle is damaged by pressure)
·Symptoms in someone over 60, far-sighted, or of East Asian or Inuit descent (these groups have narrower drainage angles and higher risk)

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Workup

·Intraocular pressure (IOP) measurement by applanation tonometry
·Gonioscopy with a Goldmann or Zeiss goniolens
·Visual acuity testing (reading an eye chart at 20 feet)
·Dilated fundoscopy (ophthalmoscopy) to examine the optic nerve head
·Anterior-segment optical coherence tomography (AS-OCT) or ultrasound biomicroscopy (UBM)
·Slit-lamp examination for cells and flare in the anterior chamber
·Visual field testing (perimetry)
·Optical coherence tomography (OCT) of the optic nerve head and retinal nerve fiber layer

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Treatment

·Intravenous hyperosmotic agent: mannitol 20% IV (1–2 g/kg over 30–60 minutes) OR oral glycerin 50% solution (1–1.5 g/kg)
·Topical beta-blocker (timolol 0.5% eye drops, one drop twice) and topical alpha-2 agonist (apraclonidine 1% or brimonidine 0.2%, one drop)
·Carbonic anhydrase inhibitors: oral acetazolamide 500 mg OR topical dorzolamide 2% or brinzolamide 1% eye drops
·Topical pilocarpine 1–2% eye drops (one drop every 15 minutes for two doses, then every 6 hours), given ONLY after IOP drops below 40 mmHg
·Topical corticosteroid eye drops (prednisolone acetate 1%, one drop every 1–2 hours initially, then tapered)
·Laser peripheral iridotomy (LPI) using Nd:YAG or argon laser
·Phacoemulsification with intraocular lens implantation (cataract surgery)

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NCLEX trap

·Angle-closure glaucoma is NOT an infection—it is a sudden blockage where the colored ring of the eye (the iris) gets shoved forward and presses against the drain (the trabecular meshwork, a tiny mesh of tissue near the edge of the iris that lets fluid leave the eye), trapping fluid inside. The pressure shoots up fast and can kill the optic nerve (the cable made of over a million nerve fibers that sends pictures from the eye to the brain) if not relieved within hours. The first move is to LOWER the eye pressure with medications—timolol drops (a beta-blocker that stops the ciliary body, the ring of tissue behind the iris, from making fluid), acetazolamide pills or IV (blocks the carbonic anhydrase enzyme so the fluid-making cells slow down), or IV mannitol (pulls extra water out of the eye by making the blood more concentrated so water follows it out)—then call ophthalmology (the eye surgery specialists) to do an emergency laser procedure called iridotomy that burns a tiny hole in the edge of the iris so trapped fluid can escape. Antibiotics do nothing here because there are no germs to kill.
·Angle-closure glaucoma often causes nausea and vomiting because the sudden spike in eye pressure triggers the trigeminal nerve (the big nerve that carries pain signals from the face and eye, cranial nerve V), which sends alarm signals to the area postrema and nucleus tractus solitarius in the medulla (the lower part of the brainstem that controls vomiting). Always ask about vision changes and eye pain when someone has sudden unexplained nausea—especially if they are older, farsighted, or took a medication that widens the pupil (like antihistamines such as diphenhydramine in Benadryl, decongestants like pseudoephedrine in Sudafed, or certain antidepressants like amitriptyline). The real emergency is the eye, not the stomach—treating only the nausea while the eye pressure stays sky-high will cost the patient their vision.
·A fixed, mid-dilated pupil in ONE eye—along with severe pain, redness, and a rock-hard eyeball—is the hallmark of angle-closure glaucoma, not a stroke. The pupil is stuck because the iris is shoved forward and pressure is so crushing that the tiny muscles that control the pupil (the iris sphincter muscle that makes it smaller and the iris dilator muscle that makes it bigger) cannot work—they are paralyzed by the extreme pressure and lack of blood flow (ischemia, meaning not enough blood is reaching the tissue to feed it with oxygen). A head CT will waste precious time. Check the eye pressure right away (with a tool called a tonometer that gently touches or blows air at the cornea) and call ophthalmology immediately. Brain imaging can wait unless there are clear brain signs like weakness on one side, slurred speech, confusion, or loss of consciousness.
·Many common medications—including antihistamines (like diphenhydramine in Benadryl), decongestants (like pseudoephedrine in Sudafed), tricyclic antidepressants (like amitriptyline), anticholinergics (like scopolamine patches for motion sickness or medications for overactive bladder), and some anti-nausea drugs (like promethazine)—can widen the pupil by blocking acetylcholine receptors or stimulating the sympathetic nervous system (the body's 'fight or flight' system that uses norepinephrine). In someone whose drainage angle is already narrow (common in older adults and farsighted people), this pupil dilation pushes the iris forward and can trigger angle-closure. This is NOT a coincidence; it is a known and preventable cause. Always ask about recent medication or eye-drop use when someone shows up with sudden eye pain and vision loss.
·Pain relief is kind and important, but angle-closure glaucoma will NOT go away without treatment—the pressure will stay dangerously high and the optic nerve will die cell by cell, causing permanent blindness within hours to days. You MUST give medications to drop the pressure fast (topical timolol to cut fluid production, oral or IV acetazolamide 500 mg to block the enzyme that helps make fluid, IV mannitol to pull water out of the eye by making the blood saltier so fluid follows, and a topical alpha-agonist like apraclonidine to further reduce production) while you call ophthalmology for emergency laser peripheral iridotomy (LPI, a procedure that uses a laser to punch a tiny hole in the iris so fluid can drain). Time is vision—every hour you wait, more optic nerve fibers die and will never come back. Watching and waiting is a recipe for blindness.

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