Why Do I See Halos Around Lights?

Seeing halos around lights is common when looking directly at headlights or lamps, especially at night. Sometimes these halos are harmless and just a typical response from the eye or may even be simply a result of wearing glasses or contact lenses.

However, halos can be a concern when other symptoms happen at the same time. They could be a side effect of other diseases, such as cataracts.

This article looks at some of the medical reasons why you might see halos around bright lights. It also discusses treatment for the conditions that may cause you to see halos.

Causes

Seeing halos around lights is a result of diffraction, an effect that occurs when the light bends while entering the eye. Diffraction can sometimes be caused by glasses and contact lenses, but it can also be a disease's side effect.

Cataracts

Seeing halos is one of the most common symptoms of cataracts, especially in posterior subcapsular cataracts. This type of cataract causes light sensitivity, blurred near vision, and glare and halos around lights. It is more common among people who have diabetes or who have been taking steroids for extended periods of time.

Fuchs' Dystrophy

This disease makes the cornea swell, causing the light to bend when entering the eye. It is a hereditary, progressive disease of the cornea.

In the early stages of this condition, excess fluid builds up overnight and causes blurry vision upon awakening. The blurry vision may improve over the course of a few hours. In later stages, the blurry vision will last longer, sometimes for most of the day.

Other symptoms of Fuchs' dystrophy include:

• Halos
• A gritty feeling in the eye
• Pain and discomfort, especially in bright light

Fuchs' Dystrophy is more common in people 50 years old or over.

Glaucoma

Seeing halos around lights is one of the symptoms of angle-closure glaucoma, a type of glaucoma in which there's high and sudden pressure in the eye due to the inability of fluid to leave the eye properly. This condition is considered an emergency and can lead to blindness within days if not treated.

Migraines

Some people who get a migraine might experience a phase before the migraine attack called migraine aura, in which they have vision disturbances that could include seeing halos around lights. The period can last anywhere from five minutes to an hour and the symptoms may change during that time.

LASIK

After LASIK surgery, it's common to see halos around lights, most often at night or in dim light. This is a side effect of your eyes trying to adjust to your newly shaped cornea. Vision issues typically last for a couple of weeks and then resolve on their own.

Dry Eye Disease

It is not uncommon that the eye's superficial part becomes irregular when it is too dry. The unusual shape will often affect how the eye receives light and, as a result, the person starts seeing halos around bright spots. Dry eye can also cause redness, burning, pain, and stinging.

Photokeratitis

Seeing halos could be a sign of photokeratitis, a condition that occurs when unprotected exposure to ultraviolet radiation damages the outer cells of the cornea. Most often people get this painful condition from the sun reflecting off of snow or water. It usually clears up on its own within a couple days.

Treatment

You may be able to get rid of halos around lights by seeking treatment for the underlying condition that causes them. Treatment is necessary for the following conditions:

• Cataracts: The most common treatment is surgery that involves removing the cloudy natural lens and replacing it with a clear artificial lens. Although it is not an emergency treatment, the surgery will prevent vision loss.
• Fuchs’ dystrophy: Treatment depends on how the condition affects your eye’s cells. In the early stages, the treatment consists of removing the eye's fluid with a sodium chloride solution or ointment. In advanced stages, a cornea transplant can restore the vision.
• Glaucoma: Treatment includes eye drops, pills, and medicine given through an IV to reduce pressure in the eye. Some people may need an operation called an iridotomy.
• Migraine: People who experience migraine with aura can control symptoms with over-the-counter of prescription painkillers, such as triptans.
• LASIK: Wearing sunglasses can help with post-LASIK halos, as can avoiding activities that will strain your eyes, such as staring at your cell phone.
• Dry Eye Disease: The most popular treatment is artificial tears, which help lubricate the area. Doctors can also prescribe gels, ointments, oral or topical steroids. In some cases, punctal plugs may be recommended.
• Photokeratitis: Artificial tears, ointments, and over-the-counter pain relievers can help reduce symptoms until the cornea heals.

Prevention

One way to prevent seeing halos around lights is to try to avoid developing the underlying conditions that cause it. Some of these conditions, such as cataracts and Fuchs' dystrophy, can't be fully prevented, but taking care of your eyes and body can help protect against disease in general. Strategies include:

• Getting regular eye exams
• Managing other health problems, such as diabetes
• Wearing sunglasses and a hat when in the sun to avoid ultraviolet radiation
• Not smoking
• Eating a healthy diet rich in foods containing vitamins and carotenoids, such as spinach, tomatoes, and carrots
• Limiting alcohol intake

When to See a Healthcare Provider

Although many people believe that seeing halos around bright lights is not a problem, it is always good to make an appointment for an eye exam with an optometrist or ophthalmologist to have your eyes checked out even if you don't have any other symptoms. It is the only way to be sure that the halos you are seeing are harmless. 

Symptoms like blurred vision, eye pain, weak night vision, blind spots, and dry, red, and itchy eyes are red flags. If you experience any of these symptoms, you should schedule an appointment as soon as possible.

Summary

Seeing halos around lights is not a disease, but it can be the first sign that something is not well with your eyes. This type of vision change can be a symptom of cataracts, glaucoma, migraine, dry eye disease, or another condition.

Treatments for these conditions include eye drops, medication, and in some cases, surgery. While in some cases there's no way to fully prevent these conditions from developing, taking care of your eyes in general can help.

If you're seeing halos around lights, it's best to schedule an appointment with an eye care professional. If a medical condition is causing these halos, this can help you get diagnosed and treated early.