Patient guide
GLP-1 medications and your eyes: when to have an eye exam
Ozempic, Wegovy, Mounjaro, Zepbound and similar medicines do a lot of good for blood sugar, weight and the heart. A few eye changes have been linked to them. Most are uncommon, and a baseline exam with regular follow-up is how they are caught early.
By Dr. Sam Khoury, Optometrist
Reviewed October 2026
6 min read
Sudden loss or dimming of vision in one eye is an emergency, even if it is painless and even if it is only the top or bottom half of what you see. Call (609) 246-0236 the same day. If the office is closed, or you cannot reach us, go to a hospital emergency room — most have an ophthalmologist on call.
Please do not stop or change your medication because of anything on this page. That decision belongs with the doctor who prescribed it, and an eye exam gives them better information to make it.
Who should have an exam
Anyone starting or already taking a GLP-1 medication. That includes semaglutide (Ozempic, Wegovy, Rybelsus), tirzepatide (Mounjaro, Zepbound), liraglutide (Victoza, Saxenda) and dulaglutide (Trulicity). Most of the eye research so far is on semaglutide; whether the others carry the same risks is not yet known.
An exam matters most if any of these apply to you:
- You have diabetes, especially if you have already been told you have diabetic retinopathy.
- You have macular degeneration, in either eye.
- You have had a sudden loss of vision from the optic nerve before, in either eye. Talk to your prescribing doctor about it before you start.
- You have high blood pressure, high cholesterol, sleep apnea, or you smoke. These are the usual risk factors for optic nerve problems, with or without the medication.
If you take it for weight and do not have diabetes, no one may have suggested an eye exam, because you are not part of the yearly diabetic eye exam routine. You are exactly who this page is for.
When to come in
American Optometric Association guidance places people on these medications in an at-risk group, which means a baseline exam and closer follow-up rather than any single special test.
Before, or soon after, you start
An exam in the 12 months before you begin counts. Otherwise, come in within a month of your first dose.
Closer follow-up
Your interval is set at the baseline visit. It is shorter if you have diabetic retinopathy or another finding worth watching.
At least once a year
For as long as you take the medication. If you have diabetes, this can be the same visit as your yearly diabetic exam.
Already been on it for a while without an exam? Come in now. A first exam a year in is far better than none.
What these medications can do to the eye
Retinopathy can temporarily worsen
When blood sugar comes down quickly, existing diabetic retinopathy can get worse for a while before the long-term benefit of better control takes over. In the large semaglutide heart trial, retinopathy complications were somewhat more common than on placebo, mostly in people who already had retinopathy. This is a reason to be checked, not a reason to avoid better blood sugar.
Sudden loss of blood flow to the optic nerve
Called NAION (non-arteritic anterior ischemic optic neuropathy). It usually shows up as a sudden, painless dimming or loss of vision in one eye, often noticed on waking. Sometimes only the top or bottom half of the view is affected. The vision lost usually does not come back, which is why it needs to be seen the same day. UK and European regulators now list it as a very rare side effect of semaglutide, and their advice is to stop the drug if it is confirmed.
Some people are born with a small, crowded optic nerve, which is the strongest known risk factor. A baseline exam tells you whether you are one of them, and gives your prescribing doctor that information before it matters.
Macular degeneration
A few studies in people with diabetes have suggested a link with the wet form of macular degeneration. The evidence is weaker than for the two changes above, but if you already have macular degeneration, it is one more reason to keep your follow-up visits.
Keeping the risk in proportion
The UK medicines regulator estimates the optic nerve problem affects up to 1 in 10,000 people taking semaglutide. Some researchers argue that much of the signal reflects publicity rather than the drug itself. The ophthalmology societies do not recommend an eye exam only to predict this one problem.
The baseline exam is worth having anyway. It checks for diabetic retinopathy. It records what your optic nerve and retina look like now, so a later change can be judged against it. And it catches the ordinary things an eye exam always finds.
What happens at the visit
It is a comprehensive eye exam with particular attention to the optic nerve and the retina. Everything is done here, at the same visit:
- Vision and eye pressure, with pressure measured without the puff of air.
- A wide view of the retina, about 200 degrees in one image, to look for diabetic changes and bleeding.
- Layer-by-layer scans of the optic nerve and macula, which show swelling and early change before you notice anything, and become the baseline every later visit is compared with.
- Peripheral vision testing, which records how the optic nerve is working, not just how it looks.
- A look at the size and shape of the optic nerve, to see whether it is the small, crowded kind.
Plan on dilating drops for the baseline visit, since this is the one exam where a close, three-dimensional look at the optic nerve matters most. Near vision stays blurry for about four hours, so bring sunglasses. Bring the name and dose of your medication and when you started it.
A written summary goes to the doctor who prescribes your medication, so the eye findings are part of their decisions.
Insurance: whether the visit goes through your medical or your vision plan depends on why you are coming and on your plan. Call and we will check before your appointment rather than after. Vision plan or medical insurance explains the difference.
Warning signs between visits
Call the same day
Sudden dimming, blurring or loss of vision in one eye. A dark or missing area in the top or bottom half of your view. Colors looking washed out in one eye. Do not wait to see whether it clears.
If the office is closed, or you cannot reach us, go to a hospital emergency room — most have an ophthalmologist on call.
Check each eye on its own
Once in a while, cover one eye and look at something with straight edges, like a doorframe. Then switch. With both eyes open, a good eye can hide a problem in the other one for days.
Call for an appointment
Vision that has slowly become blurrier, more trouble reading or seeing at night, or new straight lines looking wavy. These are not emergencies, but they are worth a visit before your next scheduled one.
For referring physicians
Fax a referral or office note to (609) 855-5028 with the drug, dose and start date, whether it is prescribed for diabetes or weight management, and any known eye history. We call the patient to schedule, and a written report with the baseline findings and the recommended follow-up interval comes back to your office.
If we find diabetic retinopathy, a crowded optic disc, or anything else relevant to the medication, the report says so plainly, so it can be weighed alongside the systemic benefit.
Questions?
Call (609) 246-0236 and we will be glad to help.
Khoury Eye Care, Hamilton Mall, 4403 Black Horse Pike, Mays Landing, inside LensCrafters on the second level.
Sources
The figures and recommendations on this page come from the following. Ask at your visit if you would like a copy of any of them.
- American Optometric Association. Glucagon-like Peptide-1 Receptor Agonists and Ocular Health: Guidance for Optometric Practice. 2025.
- Marso SP, Bain SC, Consoli A, et al. Semaglutide and cardiovascular outcomes in patients with type 2 diabetes (SUSTAIN-6). New England Journal of Medicine. 2016;375(19):1834-1844.
- Hathaway JT, Shah MP, Hathaway DB, et al. Risk of nonarteritic anterior ischemic optic neuropathy in patients prescribed semaglutide. JAMA Ophthalmology. 2024;142(8):732-739.
- European Medicines Agency, Pharmacovigilance Risk Assessment Committee. Non-arteritic anterior ischaemic optic neuropathy listed as a very rare side effect of semaglutide medicines. June 2025. The UK MHRA issued corresponding advice.