Date: 2026-04-16 Ticket: MC-629 Subject: ~3-minute "grey shutter" over one eye — cause investigation
The "grey shutter pulled down, then slowly pulled away" pattern over ~3 minutes is textbook amaurosis fugax (transient monocular vision loss, TMVL) — it is NOT the tirzepatide ocular pattern. This symptom description warrants urgent medical workup, not just watchful waiting. The tirzepatide angle is a red herring for this specific episode — but worth flagging to the doctor.
The documented GLP-1 ocular signal is NAION — non-arteritic anterior ischemic optic neuropathy — which is:
Evidence base: - JAMA Ophthalmology (March 2025) case series: 9 patients on semaglutide/tirzepatide, 7 with NAION, mean age 57 — all permanent vision loss, not transient. (JAMA Ophthalmol) - JAMA Network Open (2025) cohort: 0.04% (35/~85,000) on semaglutide/tirzepatide developed NAION over 2 years vs 0.02% controls — small absolute risk, real signal. (JAMA Netw Open) - MDL 3163 active (Dec 2025) — group litigation for Mounjaro NAION cases. (Robert King Law) - Reddit r/Mounjaro / r/Zepbound: blurry vision is very common (lens osmotic shifts from glucose drop, usually self-limiting). NAION is rare but actively discussed. The "3-minute curtain then fully resolves" pattern does not appear as a recognised tirzepatide trope on the forums.
So: keep it on the doctor's radar, but it doesn't fit.
Elmar's description ("grey shutter pulled over my eye, then slowly pulled away", ~3 minutes, one eye, full resolution) matches amaurosis fugax almost exactly. From StatPearls and Medscape:
"A curtain or shade coming down over the visual field... painless, monocular, lasting seconds to minutes, with full recovery."
Episodes of 1–10 minutes are most suggestive of carotid / embolic aetiology.
| # | Cause | Likelihood | Why relevant |
|---|---|---|---|
| 1 | Carotid artery stenosis / embolic TIA | HIGH | The #1 cause of 1–10 min monocular grey-out. Atheroma in internal carotid throws tiny platelet/cholesterol emboli into the ophthalmic artery. Precursor to stroke. |
| 2 | Cardiac embolism (AFib, valve disease, PFO, atrial myxoma) | MODERATE | Same mechanism, different source. Worth checking pulse rhythm + echocardiogram. |
| 3 | Retinal migraine / ocular migraine | MODERATE | True retinal migraine is monocular, reversible, lasts <60 min. More likely in migraine sufferers (Elmar has migraine-like "stars"). Diagnosis of exclusion — must rule out vascular causes first. |
| 4 | Retinal vasospasm | LOW-MODERATE | Transient spasm of retinal arterioles. Often migraine-adjacent. |
| 5 | Giant cell arteritis (GCA) | LOW at 50 (usually >55) | Would typically have jaw claudication, scalp tenderness, new headache, elevated ESR/CRP. Urgent if suspected — can cause permanent blindness. |
| 6 | Hypercoagulable state | LOW | Antiphospholipid syndrome, polycythaemia. Bloods will screen. |
| 7 | Raised intracranial pressure (papilledema) | LOW | Usually causes brief seconds-long obscurations, often postural. |
| 8 | Vitreous detachment / retinal tear | LOW | Usually accompanied by flashes + floaters + visual field defect that doesn't resolve. |
The photopsias triggered by bright light are more likely:
These are probably not the same thing as the grey-shutter episode.
This warrants same-week medical review, not "keep an eye on it." Specifically:
Red flags that mean go to A&E immediately, not wait for GP: - Episode recurs and doesn't fully resolve - Any weakness/numbness on one side, slurred speech, facial droop (stroke) - New severe headache, jaw pain on chewing, scalp tenderness (GCA) - Vision loss becomes permanent
50yo male on tirzepatide. Single episode transient monocular vision loss ("grey shade descending, then receding") lasting ~3 minutes with full recovery. Consistent with amaurosis fugax. Requesting carotid duplex, ECG + Holter, echo, ESR/CRP, lipids, dilated fundoscopy. Separate history of photopsia in bright light, suspected migraine aura — open to discuss.
This is research, not medical advice. See a doctor this week.