Urrets-Zavalia Syndrome (UZS)

Urrets-Zavalia syndrome is a rare complication after eye surgery where the black center of the eye (the pupil) becomes stuck in a large, round, and non-reactive position. The pupil does not get smaller in bright light and does not grow with darkness the way it should. This “fixed, dilated pupil” often comes with thinning and damage of the colored part of the eye (iris atrophy) and may also be linked to spikes in eye pressure or new adhesions in the drainage angle. The most classic setting is after corneal transplant surgery, especially in eyes with keratoconus, but it has been reported after many other anterior-segment procedures too. The leading theory is brief but damaging loss of blood flow to the iris (iris ischemia)—often triggered by sudden high eye pressure or prolonged strong dilation—which injures the tiny muscle that makes the pupil constrict, leaving it paralyzed. NCBIEyeWiki

Urrets-Zavalia syndrome is a rare complication that can happen after eye surgery—most famously after corneal transplants. The hallmark sign is a fixed, wide (dilated) pupil that does not get smaller in bright light and often comes with glare, halos, and light sensitivity. In some people, it also leads to iris atrophy (thinning of the iris tissue) and secondary angle-closure glaucoma if the peripheral iris sticks to or crowds the eye’s drainage angle. The most accepted cause is iris ischemia—the tiny blood vessels of the iris don’t deliver enough blood/oxygen—often triggered by very high eye pressure or mechanical factors around the time of surgery. NCBIEyeWikiWiley Online Library

Urrets-Zavalia syndrome is a post-surgical pupil problem. After certain operations in the front of the eye—classically a full-thickness corneal transplant (penetrating keratoplasty)—the pupil of one eye becomes stuck in a wide-open position and doesn’t respond to light. The person sees intense glare and halos, feels photophobia (light hurts), and may have a cosmetic difference between the two eyes. Over weeks to months, some people partially recover a bit of pupil reaction; others remain persistently dilated. In more severe forms, the iris tissue itself becomes thin and atrophic, and the peripheral iris can adhere to the cornea or the eye’s drain (trabecular meshwork), narrowing or closing the angle and raising eye pressure—this is where vision risk lies. The most widely supported mechanism is iris ischemia: brief but harmful loss of blood flow to the iris sphincter muscle (the “tightening” muscle of the pupil). Common drivers include spikes of intraocular pressure (IOP) soon after surgery, strong or long-acting dilating drops, viscoelastic or air/gas trapped in the front chamber, and excess manipulation or trauma to the iris. UZS has also been reported after modern lamellar grafts (DALK, DSAEK/DMEK), cataract surgery, scleral-fixated or phakic IOL procedures, and even after non-transplant anterior segment interventions—so the syndrome is not limited to corneal transplants. EyeWikiPubMedPMC+1

---

Why it happens — the core mechanism

Think of the iris as a thin donut of muscle and blood vessels. If pressure inside the eye rises sharply or if the iris is held widely dilated for a long time, blood flow through those delicate vessels can be pinched off. Without oxygen, the pupil-tightening muscle (sphincter) becomes weak or scarred, so the pupil stays big and unresponsive. This is why UZS often shows up days to weeks after surgery, when pressure spikes or retained air/gas/viscoelastic block the pupil, or when strong dilating drops were used. NCBIPubMedPMC

---

Types of Urrets-Zavalia Syndrome

Doctors do not use one rigid “typing” system for UZS, but in day-to-day care it is helpful to group cases by where they occur and how they look. Here are practical, clinic-friendly “types,” each explained in plain language:

1. Classic post-penetrating-keratoplasty UZS
   This is the original description: a fixed wide pupil with iris atrophy after full-thickness corneal transplant (PK), often in keratoconus. Spikes in eye pressure, tight dilation, or air/gas in the front chamber are common triggers. ScienceDirectEyeWiki

2. Keratoplasty-related UZS beyond PK
   The same pattern can follow DALK, DSAEK, and DMEK (partial-thickness grafts), sometimes even bilaterally. Air or gas used to hold grafts in place can block the pupil or raise pressure, which favors iris ischemia. PMCPubMed

3. Refractive and phakic IOL–related UZS
   Cases are reported after LASIK and after phakic IOL/ICL implantation. Retained viscoelastic, pressure spikes, or prolonged dilation can set the stage. ResearchGateBioMed CentralPMC

4. Cataract, IOL exchange, and scleral-sutured IOL UZS
   The pupil can become fixed after cataract-related procedures or secondary IOL fixation, even when surgery itself was uneventful, likely for the same pressure-and-ischemia reasons. PMC

5. Glaucoma surgery–related UZS
   Although unusual, UZS has occurred after trabeculectomy or combined glaucoma procedures when postoperative pressure fluctuated (very low, then high), stressing iris perfusion. Lippincott Journals+1

6. Posterior segment surgery–associated UZS
   Rarely, UZS appears after vitreoretinal operations; mechanisms again point to pressure changes and anterior segment ischemia. Directory of Open Access JournalsSemantic Scholar

7. Trauma/foreign-body–associated UZS (UZS-like picture)
   An intraocular metallic foreign body can present with a large, atonic pupil that mimics UZS; the underlying injury and pressure/inflammation may damage the sphincter. AME Case Reports

8. Medication-accentuated UZS
   Strong or prolonged mydriatics (e.g., atropine, strong phenylephrine) can worsen iris ischemia if pressure rises, helping to lock the pupil in dilation. NCBIEyeWiki

---

Causes

In many patients, more than one factor is present. The common thread is reduced blood flow to the iris sphincter plus mechanical or drug-induced dilation.

1. Sudden rise in intraocular pressure (IOP)
   A rapid IOP spike compresses iris blood vessels, starving the sphincter of oxygen and causing lasting paralysis. This is the single most consistent risk across reports. PubMed

2. Retained viscoelastic
   Leftover gel from surgery can block fluid outflow, causing pressure spikes and pupil block, which predispose to iris ischemia. NCBI

3. Air or gas in the anterior chamber
   In keratoplasty and endothelial grafts, air/gas bubbles can plug the pupil, raise IOP, and press the iris backward, contributing to ischemia. PMC

4. Prolonged or strong pharmacologic dilation
   Atropine or strong phenylephrine hold the pupil wide for hours. If blood flow drops at the same time, sphincter damage is more likely. NCBIEyeWiki

5. Keratoconus anatomy and PK setting
   The classic setting (keratoconus + PK) involves surgical steps and postoperative care that make pressure spikes and wide dilation more likely. ScienceDirectEyeWiki

6. Pupil block without a patent iridotomy/iridectomy
   If aqueous humor cannot pass forward, pressure builds behind the iris, causing a block and ischemia. PubMed

7. Tight bandage or early tamponade strategy
   Strategies that over-tamponade the anterior chamber (e.g., too much gas) can inadvertently raise pressure and impair iris perfusion. PMC

8. Intraoperative iris handling or sphincter trauma
   Direct traction or thermal damage weakens the sphincter so it cannot recover from postoperative stressors. (Mechanistic inference consistent with case series.) NCBI

9. Inflammation in the anterior chamber
   Postoperative iritis can cause vascular spasm and microthrombosis around the sphincter, adding to ischemic risk. (Mechanism summarized in reviews.) SciELO

10. Post-LASIK or surface ablation context
    Although rare, refractive surgery has been followed by UZS, likely via IOP changes or drug-induced dilation around surgery. ResearchGate

11. Phakic IOL / ICL implantation
    ICL or iris-claw lenses can be associated with retained viscoelastic or pupil block, producing UZS. BioMed CentralHealio Journals

12. Scleral-sutured or secondary IOL surgery
    Fluid dynamics and postoperative IOP swings in these procedures have been linked to UZS in case reports. PMC

13. Glaucoma procedures with pressure fluctuation
    Hypotony followed by rebound high IOP can disturb iris perfusion and lead to a fixed large pupil. Lippincott Journals+1

14. Posterior segment (retina) surgery
    Rarely, anterior segment blood flow is affected after vitrectomy or other posterior surgery, triggering UZS. Directory of Open Access Journals

15. Tight or prolonged eyelid speculum time
    Long surgeries with sustained pressure on the globe can temporarily raise IOP, adding risk, especially when combined with dilation. (Mechanistic inference supported by pathophysiology.) NCBI

16. Small or crowded anterior chamber
    Eyes with narrow angles or crowding are more prone to pupil block and pressure spikes around surgery. (Risk principle echoed in reviews.) SciELO

17. Young age with strong sympathetic tone
    Younger irides can dilate widely and hold dilation, which may worsen ischemia when pressure rises. (Inferred risk pattern across case series.) NCBI

18. Use of long-acting cycloplegics post-op
    Keeping the pupil wide for pain control can prolong ischemic conditions if IOP is not carefully managed. NCBI

19. Lack of early IOP monitoring and relief
    Delayed detection of a pressure spike allows longer ischemic time to the iris sphincter. (Prevention emphasized in reviews.) PubMed

20. Trauma/foreign body with secondary pressure issues
    Direct injury plus inflammatory pressure changes may produce a UZS-like fixed dilated pupil. AME Case Reports

---

Symptoms

1. A very large pupil that never gets small
   The black center looks bigger than the other eye and stays big in bright light.

2. Strong light sensitivity (photophobia)
   Light pours into the eye through the wide pupil, so normal lighting can feel harsh and painful. BioMed Central

3. Glare and halos
   At night, headlights make rings and streaks, because light is not being filtered by a normal, small pupil. BioMed Central

4. Trouble seeing up close
   If you still have your natural lens, the eye loses depth-of-field from the big pupil, making near work harder.

5. Reduced contrast or hazy vision
   Too much stray light lowers contrast, so details look washed out.

6. Anisocoria
   One pupil is clearly bigger than the other. This asymmetry is often the very first thing people or family notice.

7. Cosmetic concern
   The eye may look different in photos or mirrors, which can be distressing.

8. Headaches or eye strain in bright places
   Because the iris cannot protect the retina by getting smaller, bright rooms or outdoors can trigger strain.

9. Night driving difficulty
   Halos and glare become obvious with oncoming lights.

10. Blur or fluctuating vision if pressure rises
    If eye pressure is elevated, you may feel ache and notice blur that changes through the day.

11. Pain or redness (when IOP is high or the eye is inflamed)
    Some cases include aching pain, tender eye, or redness.

12. Watering or tearing
    Reflex tearing can happen with bright light and discomfort.

13. Dryness sensation
    Because people squint to cope with light, the eye surface can feel dry or irritated.

14. Shadowing at the edge of vision
    New adhesions in the angle or iris changes can create subtle visual artifacts.

15. Anxiety about sudden change
    A “stuck” pupil after surgery is frightening; worry and sleep disruption are very common and very understandable.

---

Diagnostic tests

A) Physical exam tests

1. Pupil size and light reaction in bright and dim rooms
   The doctor measures the pupil and shines a light. In UZS, the pupil is large and barely reacts. This quick bedside check is the core finding. NCBI

2. Swinging flashlight test
   Confirms the afferent pathway is intact and that the problem is mechanical/ischemic at the iris, not from optic nerve damage.

3. Near response (accommodation test)
   Seeing if the pupil constricts with near focus helps separate UZS (usually no constriction) from some neurologic pupil problems.

4. Slit-lamp biomicroscopy of the iris
   The microscope exam looks for iris atrophy, transillumination, or sphincter tears typical of UZS. NCBI

5. Intraocular pressure (tonometry)
   Because pressure spikes are central to UZS, measuring IOP is essential, often repeatedly in the early postoperative period. PubMed

B) “Manual” office tests

6. Pharmacologic miotic testing (e.g., pilocarpine 1–2%)
   In UZS the damaged sphincter often shows little or no constriction even to strong pilocarpine, helping rule out other causes such as Adie’s denervation. NCBI

7. Phenylephrine challenge
   A phenylephrine drop checks dilator function and can help characterize iris muscle balance; in UZS, sphincter failure dominates.

8. Gonioscopy (contact lens angle exam)
   The doctor gently places a special lens to inspect the drainage angle for peripheral anterior synechiae (PAS) that sometimes form with UZS and can worsen pressure control. AAO

9. Photopic/mesopic pupillometry
   Objective measurement of pupil size in light and dark documents the fixed dilation and tracks change over time.

10. Glare disability testing
    Quantifies how much stray light affects functional vision in daily life, guiding tinted-lens support.

C) Laboratory & pathological tests

11. Basic inflammation labs when history is unclear
    If the story is not clearly postsurgical, simple markers (e.g., ESR/CRP) can help screen for active inflammation that might mimic or worsen symptoms (not specific to UZS but helpful in differential).

12. Infectious serology when indicated
    Rarely, tests such as syphilis serology are ordered if there is concern for neuro-ophthalmic causes of anisocoria; this is to exclude look-alikes rather than diagnose UZS.

13. Aqueous tap/cytology (exceptional cases)
    In atypical presentations with severe inflammation, the team may sample fluid to rule out infection or masquerade syndromes (uncommon in pure UZS).

14. Histopathology (research/rare surgical specimens)
    When iris tissue is available (e.g., at the time of another surgery), microscopy may show sphincter atrophy, supporting the ischemia mechanism. (Described in reviews.) SciELO

D) Electrodiagnostic & physiologic tests

15. Infrared pupillography / chromatic pupillometry
    Records pupil light reflex precisely; in UZS it remains flat-lined or minimal, consistent with sphincter failure.

16. Visual evoked potentials (VEP) – selected cases
    If visual complaints seem out of proportion, VEP checks the optic nerve/brain pathway to confirm the problem is ocular-front rather than neurologic.

17. Electroretinography (ERG) – selected cases
    ERG can be used when macular disease is suspected as a co-factor in reduced vision; it usually does not explain the fixed pupil but may clarify the whole picture.

E) Imaging tests

18. Anterior segment OCT (AS-OCT)
    Provides a cross-section image of the front of the eye to evaluate iris thickness, angle configuration, graft apposition, and air/gas position; helpful to document PAS or pupil block mechanisms. PMC

19. Ultrasound biomicroscopy (UBM)
    High-frequency ultrasound shows the root of the iris and ciliary body, mapping any forward bowing or block that might have precipitated ischemia.

20. Scheimpflug imaging / anterior segment photography
    Captures objective pupil size and iris changes over time; useful for documentation and patient counseling.

Non-pharmacological treatments (therapies & practical supports)

(These support comfort and function. They do not “cure” an ischemic, atonic pupil, but they can be life-changing for glare/photophobia.)

1. Photochromic eyeglasses: lenses that darken outdoors; reduce ambient light overload.

2. Polarized sunglasses: cut horizontal glare (roads, water).

3. Blue-attenuating/tinted filters (FL-41, amber, orange): many patients feel less glare and migraine-type light discomfort.

4. Brimmed hats/visors outdoors: simple but effective overhead light control.

5. Task lighting control: indirect lamps; avoid bare bulbs in the field of view.

6. Anti-glare screen filters and dark-mode UI at computers/phones.

7. Night-driving strategies: plan routes, increase following distance, consider a passenger “co-pilot”; avoid rainy nights when possible.

8. Painted/tinted soft contact lens with smaller artificial pupil (“iris print” lenses) to optically stop down the aperture and reduce halos.

9. Rigid gas permeable with opaque aperture in select cases for better optics.

10. Low-vision rehabilitation consult for glare-management training and device selection.

11. Workplace adjustments (glare shields, display relocation, softer ambient lighting).

12. Treat coexisting dry eye (blink breaks, warm compresses, humidifier) to reduce surface scatter that worsens glare. PubMedTFOS DeWS Report

13. Photophobia diaries to identify triggers and effective strategies.

14. Psychological support if cosmetic difference or chronic light pain affects mood.

15. Protective eyewear in bright environments (stadiums, beaches, snow).

16. Gradual light re-exposure techniques to reduce light-shock.

17. Avoid unnecessary dilating drops in future care; ask providers to note UZS history. EyeWiki

18. Regular IOP checks if you’ve ever had angle narrowing or spikes. NCBI

19. Driving self-assessment (and local regulations) if glare is severe at night.

20. Education: understanding UZS reduces anxiety and improves adherence to protective measures.

---

Drug treatments

Important: No eye drop has proven, consistent ability to “reverse” a long-standing ischemic, atonic pupil. Medicines are used for (a) comfort and glare control, (b) inflammation control early on, and (c) IOP/angle safety. Doses below are typical clinical ranges—not personal medical advice. Always follow your ophthalmologist’s plan.

1. Brimonidine 0.15–0.2% (alpha-2 agonist) PRN at dusk or nightly

   • Purpose: modest physiologic miosis in dim light → less night glare for some patients.

   • How it works: reduces sympathetic-driven dilation under scotopic conditions.

   • Dose/timing: 1 drop once in evening or before night driving; effect ~4–8 h (varies).

   • Side effects: mild stinging, dry mouth; rare allergy; caution if on clonidine-like meds.

   • Evidence: reduces scotopic pupil size and night-vision complaints after refractive surgery; may help some UZS patients symptomatically even if the sphincter is weak. PMCPubMedFrontiers

2. Prednisolone acetate 1% (topical steroid) in early, inflamed cases

   • Purpose: calm anterior-segment inflammation that might worsen iris injury.

   • Dose: often QID then taper, individualized.

   • Side effects: steroid-response IOP rise; cataract risk if prolonged; infection risk.

   • Note: for symptom control early; does not fix chronic atony. NCBI

3. IOP-lowering beta blocker (e.g., timolol 0.5% BID)

   • Purpose: keep pressure safe if it’s elevated or angle is narrow.

   • Mechanism: reduces aqueous production.

   • Side effects: systemic beta-blocker effects (fatigue, bronchospasm in asthma/COPD). NCBI

4. Topical carbonic anhydrase inhibitor (dorzolamide 2% TID / brinzolamide TID)

   • Purpose: additional IOP control.

   • Side effects: bitter taste, local irritation. NCBI

5. Alpha-2 agonist (brimonidine) TID for IOP

   • Purpose: IOP control (separate from its miotic effect above).

   • Caution: avoid in infants/young children. Frontiers

6. Oral acetazolamide 250 mg q6–8h short term (or IV mannitol in acute spikes, supervised)

   • Purpose: rapid pressure reduction when angle is compromised.

   • Side effects: paresthesias, diuresis, kidney stone risk; avoid in sulfa allergy. EyeWiki

7. Pilocarpine 1–2% (miotic) trial in early or incomplete cases

   • Purpose: try to stimulate sphincter if not completely atonic.

   • Reality check: often ineffective in established UZS; may worsen inflammation or angle issues if overused.

   • Side effects: brow ache, myopic shift, risk of retinal detachment in predisposed. PMC

8. Dapiprazole 0.5% (sympatholytic) where available

   • Purpose: counteract dilator muscle tone; used off-label in case reports with pilocarpine.

   • Evidence: isolated case reports of partial improvement; availability limited. PMCSemantic Scholar

9. Short-acting cycloplegic avoidance (this is about not using further dilators)

   • Rationale: do not add more mydriasis in UZS unless specifically indicated. EyeWiki

10. IOP emergency meds per surgeon’s orders (e.g., hyperosmotics) when angle-closure risk is present.

• Purpose: protect optic nerve while definitive steps (washout, surgical pupilloplasty) are arranged. EyeWiki

---

Dietary “molecular” supplements

Honest evidence check: No supplement has been shown to reverse UZS or regenerate a damaged iris sphincter. Some nutrients may reduce glare sensitivity or support ocular surface health, which can modestly ease symptoms. Always clear supplements with your clinician (drug interactions exist).

1. Lutein (10–20 mg/day) & Zeaxanthin (2–4 mg/day): build macular pigment that filters blue light; clinical trials show improved glare disability and photostress recovery in non-UZS settings—may help comfort. PubMedBioMed CentralPMC

2. Meso-zeaxanthin (7–10 mg/day): often combined with L/Z; similar glare-filtering rationale. BioMed Central

3. Omega-3 fatty acids (EPA/DHA ~1–2 g/day): may improve dry-eye symptoms in some analyses → less surface scatter and glare. Evidence is mixed but trending supportive in recent reviews. Wiley Online Library

4. Vitamin A (only if deficient; medical supervision): deficiency causes night blindness and photophobia; do not self-dose—risk of toxicity. ScienceDirectPMC

5. Vitamin C (250–500 mg/day) &

6. Vitamin E (natural d-alpha tocopherol 100–200 IU/day): general antioxidant support; no direct UZS data.

7. Zinc (10–25 mg/day): cofactor in retinal metabolism; avoid excess (copper depletion).

8. Bilberry/anthocyanins: limited data for contrast/glare; consider as adjunct only.

9. Curcumin (phytosomal formulations): anti-inflammatory potential; ocular evidence limited.

10. Magnesium (100–200 mg/night): may reduce photophobia in migraine-linked light sensitivity for some; not UZS-specific.

---

Regenerative, stem-cell drugs

There are no approved immune-booster, regenerative, or stem-cell drugs that treat or reverse UZS. The problem in UZS is mechanical/ischemic damage to iris muscle and stroma. Below are research or conceptual areas, not clinical treatments—no dosage exists for UZS:

1. Iris tissue engineering / stem-cell–derived sphincter constructs (preclinical concept).

2. Gene or growth-factor therapies to promote vascular/nerve regeneration of iris—no human data.

3. Biomaterial scaffolds for bio-artificial iris integration (distinct from current prosthetic iris implants).

4. Neuro-regenerative peptides for autonomic neuromuscular repair—unproven in iris.

5. Rho-kinase pathway modulators aimed at ocular blood flow/repair—no UZS evidence.

6. Cell-based anti-fibrotic strategies to prevent peripheral anterior synechiae—experimental only.

Best practice today: use symptomatic aids and, when appropriate, surgical pupil reconstruction or artificial iris rather than unproven “regenerative” drugs. Major reviews emphasize that medical therapy is often inconsistent, and definitive improvement in a chronically atonic pupil usually requires surgery. EyeWiki

---

Surgeries

1. Anterior-chamber washout / spacer maneuvers (early)

   • Why: if UZS relates to blood/viscoelastic/gas or iris-cornea touch, washing out material and reforming a deep chamber can relieve iris strangulation and pressure. EyeWiki

2. Pupilloplasty (single-pass, four-throw; cerclage; sector techniques)

   • What: suture the pupil smaller and rounder; can also pull peripheral iris centrally to open a crowded angle.

   • Why: reduce glare/photophobia and prevent angle closure. Modern techniques show meaningful improvement in symptoms and anatomy. PubMedSAGE JournalsAAO

3. Iris suturing/iridoplasty for focal defects

   • What: close iris “gaps” or atrophic sectors to regularize the aperture.

   • Why: improve optical quality and cosmesis. EyeWiki

4. Artificial iris (black diaphragm IOL or custom prosthetic iris)

   • What: implant a device that creates a fixed small pupil and restores iris color.

   • Why: for severe atrophy when suturing tissue isn’t possible. EyeWiki

5. Corneal/keratopigmentation (tattooing, including femtosecond-assisted)

   • What: stain the cornea to make a smaller optical window (painted “pupil”).

   • Why: reduce light entry and improve cosmesis when other options are unsuitable. EyeWiki

---

Prevention strategies

1. Keep the anterior chamber deep throughout surgery. EyeWiki

2. Gentle iris handling—avoid trauma with blades/trephines. EyeWiki

3. Thorough viscoelastic removal from the angle at the end. EyeWiki

4. Use only small air/gas volumes when needed for graft support. EyeWiki

5. Consider pre-/intra-operative peripheral iridotomy for pupillary block risk cases. EyeWiki

6. Control IOP closely in the first 24–48 h, especially in keratoconus. EyeWiki

7. Avoid strong/long-acting mydriatics unless essential. EyeWiki

8. Manage vitreous pressure (e.g., mannitol pre-op in select PKP cases). EyeWiki

9. Plan wound architecture to minimize iris compression. EyeWiki

10. Educate patients to report severe light sensitivity or eye pain immediately after surgery.

---

When to see a doctor

• Immediately if you notice sudden severe light sensitivity, a visibly much larger pupil, eye pain, headache, nausea, or colored halos in the days after eye surgery—these can signal pressure spikes or angle closure.

• Urgently (same day) if your vision becomes blurry or you develop one-sided glare that wasn’t there before.

• Promptly if non-pharmacologic aids don’t help and you struggle to work/drive—ask about pupilloplasty or custom tinted contact lenses. NCBI

---

What to eat and what to avoid

What to eat more of (general eye-healthy pattern):

• Leafy greens (spinach, kale): natural lutein/zeaxanthin to bolster macular pigment and reduce glare sensitivity for some people. Wiley Online Library

• Colorful veggies & fruits (peppers, corn, oranges, berries): carotenoids and antioxidants.

• Oily fish (salmon, sardines): omega-3s for ocular-surface comfort. Wiley Online Library

• Eggs, dairy, liver (in moderation): vitamin A sources—but only supplement if deficient. ScienceDirect

• Hydration: keeps tear film steadier and reduces surface scatter.

What to go easy on:

• Excess alcohol (drying, affects sleep and light sensitivity).

• Very bright-screen late nights—use night mode and 20-20-20 breaks.

• Unsupervised vitamin A megadoses (risk of toxicity; supplementation should be supervised). ScienceDirect

---

Frequently asked questions (FAQ)

1. Can drops make my big pupil small again?
   Sometimes brimonidine shrinks the pupil a little in dim light and helps with night glare, but established UZS from iris ischemia often needs surgical solutions for lasting improvement. PMC

2. Will my vision be permanently damaged by the large pupil?
   The large pupil mainly causes glare/photophobia, not direct acuity loss. The real risk to vision is angle-closure glaucoma from crowding—hence the focus on IOP monitoring. EyeWiki

3. Do people ever recover spontaneously?
   Yes—a minority regain some pupil reactivity within weeks to months, especially in incomplete cases. Others remain persistently dilated. EyeWiki

4. Is UZS only after corneal transplant?
   No. It’s been reported after lamellar keratoplasties, cataract, phakic IOL, and scleral-fixated IOL surgeries, among others. PubMedPMC+1

5. Why does controlling eye pressure matter so much?
   Because pressure spikes can choke iris blood flow and worsen ischemia—prevention and early treatment are key. Wiley Online Library

6. Can tinted contact lenses really help?
   Yes—painted/tinted lenses with a smaller artificial pupil can markedly reduce glare/halos for many people when fitted by a specialist.

7. Is there a laser fix?
   Laser is not a standard cure for chronic UZS. Some iridoplasty/pupilloplasty approaches are surgical, not laser, and they aim to reconstruct a smaller pupil.

8. What about an artificial iris?
   A custom prosthetic iris can restore a small aperture and natural appearance when the native iris is too damaged. EyeWiki

9. Are there stem-cell treatments?
   No approved regenerative/stem-cell therapies exist for UZS at this time.

10. Could this be caused by my dry eyes?
    Dry eye doesn’t cause UZS, but it amplifies glare. Managing the ocular surface can improve comfort. PubMed

11. Does brimonidine work for everyone?
    No. Some pupils don’t respond (especially if the sphincter is severely atonic). Others get helpful but temporary relief. PMC

12. Is pilocarpine worth trying?
    It may be tried in early/incomplete cases, but success is inconsistent and side-effects limit use. PMC

13. Can UZS happen even if my surgery went perfectly?
    Unfortunately yes—there are reports without obvious triggers or IOP spikes, which is why it’s considered multifactorial. EyeWiki

14. If I already had UZS once, am I at risk in my other eye?
    Risk depends on surgery type and peri-operative factors, not simply on having UZS in one eye. Surgeons will take extra prevention steps if any future surgery is needed. EyeWiki

15. Bottom line for long-term care?
    Protect from glare, keep IOP in check, and discuss pupil reconstruction or prosthetic iris if symptoms limit life. Regular follow-up matters. PubMed

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members

Last Updated: August 29, 2025.