If you’ve noticed bright rings or circles around lights—especially at night—you’re not alone. Seeing halos around headlights, streetlights, or other light sources can be unsettling, but understanding what causes them and when to seek help can give you peace of mind.
At our Edmonton optometry clinic, we hear this question frequently, especially during winter months when driving at night becomes more common. Here’s what you need to know about halos, what causes them, and when it’s time to schedule an eye exam.
What Are Halos?
Halos are bright circles or rings that appear around light sources. They’re most noticeable around headlights, street lamps, or other bright lights, particularly in low-light conditions. Some people describe them as a “starburst” or “glow” effect that makes lights appear larger or more diffuse than they actually are.
While halos can be a normal response to certain conditions (like glare from wet roads or foggy windows), persistent or sudden halos may signal an underlying eye condition that needs attention.
Common Causes of Halos
1. Refractive Errors (Nearsightedness, Farsightedness, Astigmatism)
One of the most common causes of halos is an uncorrected or under-corrected refractive error. When your eye doesn’t focus light properly onto the retina, it can scatter, creating a halo effect around bright lights.
What to do: If you’re experiencing halos and haven’t had an eye exam recently, it may be time to update your prescription. Even small changes in your vision can cause noticeable halos, especially at night.
2. Cataracts
Cataracts occur when the lens of your eye becomes cloudy, scattering light as it enters the eye. This scattering creates halos, glare, and difficulty seeing clearly—especially in low-light or nighttime conditions.
Cataracts are common as we age, but they can also develop earlier due to factors like diabetes, UV exposure, or eye injury.
What to do: If you’re over 60 and noticing increasing halos, glare, or cloudy vision, schedule a comprehensive eye exam. Cataracts are treatable, and early detection helps you plan the best course of action.
3. Glaucoma
Glaucoma is a serious eye condition caused by increased pressure inside the eye, which can damage the optic nerve. In acute angle-closure glaucoma, halos around lights may appear suddenly, often accompanied by severe eye pain, headache, nausea, and blurred vision.
What to do: If you experience sudden halos with eye pain, redness, or vision changes, seek immediate medical attention. Acute glaucoma is a medical emergency that requires prompt treatment to prevent permanent vision loss.
4. Dry Eyes
Dry eyes occur when your eyes don’t produce enough tears or when tears evaporate too quickly. This can cause your cornea’s surface to become irregular, scattering light and creating halos around bright sources.
Dry eyes are especially common in Edmonton’s winter months due to indoor heating and cold, dry outdoor air.
What to do: Use artificial tears, stay hydrated, and consider a humidifier at home or work. If dry eyes persist, we can recommend prescription treatments or other therapies to improve tear production.
5. Contact Lens Issues
Wearing contact lenses that are dirty, damaged, or ill-fitting can cause halos. Protein buildup, tears in the lens, or wearing lenses past their replacement schedule can all scatter light and create visual distortions.
What to do: Clean your lenses properly, replace them on schedule, and make sure your prescription is up to date. If halos persist, schedule a contact lens fitting to ensure you’re wearing the right type and size.
6. Corneal Swelling (Edema)
Corneal edema occurs when fluid builds up in the cornea, causing it to swell. This can happen after eye surgery (like LASIK or cataract surgery), due to eye injury, or from certain eye conditions like Fuchs’ dystrophy.
What to do: If you’ve recently had eye surgery and are seeing halos, contact your eye surgeon. Mild corneal swelling often resolves on its own, but persistent swelling may require treatment.
7. Medications
Certain medications can cause halos as a side effect, particularly those that affect pupil size or tear production. Common culprits include some antihistamines, antidepressants, and medications for high blood pressure.
What to do: If you started a new medication and noticed halos shortly after, mention it to your optometrist. We can help determine if the medication is the cause and work with your doctor to explore alternatives if needed.
When Should You See an Optometrist?
While occasional halos (especially in rainy or foggy conditions) are usually harmless, you should schedule an eye exam if:
- Halos appear suddenly or worsen over time
- You experience halos along with eye pain, redness, or headaches
- You notice changes in your vision, such as blurriness or difficulty seeing at night
- You have a family history of glaucoma or cataracts
- You haven’t had a comprehensive eye exam in over a year
Early detection is key to treating many eye conditions, and a thorough exam can identify the root cause of your halos and get you on the path to clearer vision.
Protecting Your Vision This Winter
Edmonton winters bring unique challenges for eye health—dry indoor air, increased screen time, and more nighttime driving. Here are a few tips to protect your eyes this season:
- Stay hydrated and use a humidifier to combat dry eyes
- Wear sunglasses even in winter—UV rays reflect off snow and can damage your eyes
- Schedule regular eye exams to catch vision changes early
- Keep your windshield clean to reduce glare and halos while driving
- Update your prescription if you’re struggling to see clearly at night
Book Your Eye Exam Today
If you’re seeing halos around lights or experiencing any changes in your vision, don’t wait. Our experienced optometry team in Edmonton is here to help you see clearly and protect your long-term eye health.
Schedule your comprehensive eye exam today and let’s get to the bottom of what’s causing your halos.
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