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What Causes Halos in Vision?

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A point-of-view shot of a person who is seeing city lights as blurry halos.

If you’ve ever looked at a source of light and noticed a ring-like blur around it, you may be experiencing halos in your vision. This can make it difficult to navigate your environment since it can interfere with your vision—but what exactly causes halos in vision?

Typically, halos in vision are caused by a problem with how light enters your eye. This could be due to one of several different medical conditions or eye conditions or be caused by a migraine.

If you’re experiencing halos in your vision, visit your optometrist for a comprehensive eye exam so they can diagnose the cause of your halo vision.

Why Am I Seeing Halos in My Vision?

The human eye is an incredibly complex organ designed to help you see the world around you. When it’s healthy, light is refracted toward a single focal point on the retina. This is due to the circular shape of the eye. When this light reaches the retina, the eye sends the information through the optic nerve to the brain, where the brain creates the image it’s seeing. 

However, when you’re exposed to bright sources of light, it sometimes doesn’t refract properly. Instead, it undergoes a process called “diffraction.” This is caused by a problem with the natural lens on the front of your eye. If there’s an imperfection on the surface of the lens or a misshapen cornea, the light bends and spreads as it enters. 

Once the angle of the light is changed, it leads to a subtle glow or halo around sources of light. Diffraction can be caused by a few various factors, including:

  • Cataracts
  • Glaucoma
  • Migraines
  • Dry eyes

It could also be caused by recent surgery or trauma to the eye. If you notice that you regularly see halos around sources of light, you should visit an optometrist.


Cataracts are a common eye condition that occurs when the eye’s natural lens begins to become cloudy. This is caused by changes in the eye leading to proteins breaking down and clumping together, causing blurry or foggy spots in your vision.

Over time, this cloudiness begins to obstruct light and stop it from reaching the retina—or causes it to diffract due to the irregularities in the lens. This can lead to:

  • Blurriness
  • Light sensitivity 
  • Reduced ability to see colors

These are more common in older adults but can occur earlier on in life due to genetics, eye injury, or some medical conditions that affect the eye. Often, cataracts are treatable through cataract surgery.


Glaucoma is a group of eye conditions that are best characterized by damage to the optic nerve. This is caused by an excess amount of pressure inside the eye that leads to inflammation. And, if left untreated, the damage to the nerve can lead to long-term damage to your vision, with the potential of total vision loss.

Glaucoma can progress slowly with almost no symptoms, making it difficult to notice if you have glaucoma developing. This slow progress makes it essential to regularly visit your optometrist for comprehensive eye exams so glaucoma can be detected in its early stages—when it’s most treatable.

Symptoms of glaucoma include:

  • Blurry vision
  • Tunnel vision
  • Nausea or vomiting
  • Eye redness
  • Discomfort in and around the eyes

In many situations, glaucoma can cause halos around sources of bright light. These are caused by the increase in pressure—which can damage several parts of the eye. Once the pressure begins to build, it can affect the optic nerve, leading to the visual information sent to the brain being affected as well.

It can cause diffraction, the change in how light enters the eye. This increased pressure caused by glaucoma can lead to light scattering and bending poorly as it enters the cornea. This causes the halo effect around many sources of light.

A stressed young woman who is experiencing a severe headache tries to alleviate the pain by applying pressure to her temples.

Migraines & Headaches

Migraines are severe headaches that can cause a significant amount of disturbances to all your senses—including vision changes. When migraines cause halos around lights, it’s often due to a specific type of migraine called a “migraine with an aura.”

This term refers to the visual disturbances the migraine causes, like:

  • Flashing lights
  • Light sensitivity
  • Difficulty clearly seeing patterns
  • Wavy lines
  • Halos around lights

These visual problems are thought to be due to changes in the brain’s activity and blood flow and can last anywhere from a few minutes to an hour.

Dry Eye Disease

Dry eye disease is a common condition that affects millions of people every year. It’s caused by a disruption to your natural tear film but is often treatable.

Your tears are evenly spread across the surface of your eye every time you blink. But when this film is disrupted, it can eventually lead to damage to the cornea. When light enters the eye and you’re experiencing dry eye disease, it can diffract either through the tears or the damaged cornea, causing the rays to bend oddly—causing the halo effect.

Clear Up Your Vision

Experiencing halos in your vision can be irritating. However, it doesn’t always mean something catastrophic. If you’re experiencing halos when you look at a source of bright light, book an appointment with the team at Foothill Optometric Group. We can perform a comprehensive eye exam to help diagnose the cause of your vision problems.

Written by Total Vision

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