Is it normal to see halos and glare when driving at night?

Is it normal to see halos and glare when driving at night?

Many drivers notice halos (rings of light) or glare (bright streaks or starbursts) around oncoming headlights, street lamps or reflective road signs when driving in low-light conditions. You’re not alone. In most cases, mild halos and glare at night are common and benign. However, persistent, worsening or vision-threatening symptoms can signal an underlying eye condition that deserves prompt attention.

Below, we explain:

1. What halos and glare are
2. Why they occur, especially at night
3. When they’re considered normal
4. Common causes—from harmless to serious
5. Practical tips to reduce them
6. When to seek professional help

1. What exactly are halos and glare?

• Halos: Colored or white rings that appear to encircle bright light sources (e.g., headlights).
• Glare: Excessive brightness—either as starbursts, streaks, or general haze—that makes it hard to see details around lights.

Both phenomena stem from light scattering inside the eye and can momentarily impair your ability to see the road clearly.

2. Why halos and glare are more noticeable at night

At night, your pupils dilate (enlarge) to let in more light. While this helps you see better in the dark, it also:

• Exposes more of the eye’s optical imperfections (corneal irregularities, lens imperfections).
• Increases scattering of incoming light off the edges of the pupil and ocular structures.
• Makes you more sensitive to oncoming headlights and streetlights.

The result: lights appear brighter, bloom into halos, or streak into glare.

3. When halos and glare are considered “normal”

Mild halos or glare that:

• Occur occasionally, only in very dark settings, and don’t interfere with your driving safety.
• Improve with anti-reflective (AR) glasses or when looking through clean windshield/glasses.
• Don’t worsen rapidly or come with other vision changes (like sudden blurred spots).

These are often just a quirk of nighttime vision and aren’t a cause for alarm.

4. Common causes of halos and glare

1. Physiological scattering

   • Natural light scattering in a healthy eye, especially with dilated pupils.

2. Refractive errors

   • Nearsightedness, farsightedness or astigmatism. Uncorrected or under-corrected prescriptions can amplify halos/glare.

3. Dry eye

   • An unstable tear film scatters light.
   • Symptoms: scratchy, burning feeling; fluctuating vision.
   • Treatment: artificial tears, eyelid hygiene.

4. Lens changes (cataracts)

   • As the eye’s natural lens becomes cloudy, it scatters light more.
   • Early cataracts often present with increased glare and halos at night.
   • Referenced evidence: Optical imperfections in cataract patients cause significant photic disturbances when pupils dilate.

5. Multifocal intraocular lenses (IOLs)

   • After cataract surgery, some IOL designs split incoming light into near and distance focal points.
   • Kohnen & Siedlecki (2004) found that larger pupil sizes can worsen halos after multifocal IOL implantation.
   • Mönestam (2008) reported that up to 30% of patients with multifocal IOLs experience noticeable halos/glare—though many adapt over months.

6. Corneal issues

   • Scarring, edema (swelling), or dystrophies.
   • Even mild corneal swelling (from contact lens over-wear) can create starbursts around lights.

7. Medication side effects

   • Certain glaucoma drops or systemic medications (e.g., some antihistamines) can dilate pupils further or change tear film quality.

8. Other eye diseases

   • Early glaucoma, diabetic retinopathy or optic nerve conditions can cause light sensitivity and glare.
   • Migraines with visual auras (flashing lights, fortification spectra) are less common but can mimic halos.

5. Tips to reduce halos, glare and improve night vision

Even if your halos and glare are “normal,” you can take steps to make night driving safer and more comfortable:

– Keep your windshield and eyeglass lenses clean. Smudges and streaks worsen glare.
– Wear high-quality anti-reflective (AR) coated lenses.
– Use low-beam headlights when you can and reduce dashboard brightness.
– Space out oncoming cars: aim your gaze slightly to the right edge of the road if a vehicle’s headlights blind you.
– Maintain proper headlight alignment and cleanliness on your vehicle.
– Stay hydrated and treat dry eye with preservative-free artificial tears.
– Limit screen time before bed—blue light from phones/tablets can cause temporary glare sensitivity.

6. When to seek professional help

Although mild halos and glare are common, you should speak to an eye care professional if you experience:

• Sudden onset of large halos around all lights.
• Rapid worsening of glare that interferes with safe driving.
• Associated blurred vision, dark spots, flashes or “curtain” in your vision.
• Pain, redness or severe light sensitivity that doesn’t improve with basic remedies.

You might also consider doing a free, online symptom check for Blurred vision to better understand your risk factors and next steps.

7. Possible serious conditions

In rare cases, halos and glare can be a sign of:

• Acute angle-closure glaucoma (an emergency).
• Corneal infections or ulcers.
• Retinal detachment (flashes, floaters, shadow in vision).
• Neurological causes—posterior optic neuropathies or brain lesions.

If you experience any sudden, severe visual symptoms or eye pain, seek immediate medical attention.

Summary

• Occasional halos and glare at night are often harmless and related to pupil dilation and light scattering.
• Common causes include refractive errors, dry eye, early cataracts or multifocal IOLs after surgery.
• Good hygiene for glasses, appropriate lens coatings and proper headlight maintenance can help.
• Persistent, worsening or accompanied by other vision changes warrants prompt evaluation.

Always speak to a doctor about any vision changes that could be life threatening or serious. A qualified eye care professional can perform a complete eye exam, determine what’s normal for you, and recommend effective treatments or lifestyle adjustments for clearer, safer night vision.