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Halos Around Lights: Causes, Warning Signs and What Helps
Halos around lights are glowing rings that appear around bright lights, most often at night. Common causes are cataracts, dry eye, an out-of-date glasses prescription, healing after laser eye surgery and multifocal or trifocal lens implants. Halos together with severe eye pain, a red eye, headache or nausea can be acute angle-closure glaucoma, an emergency. New halos should be checked by an eye specialist, such as the surgeons at Laser Istanbul Clinic.
What are halos around lights?
A halo is a ring or glow of light that surrounds a bright source, such as a street lamp, car headlights or a phone screen in a dark room. The NHS lists "glowing rings (halos) around lights" among the symptoms of cataracts, and it lists seeing "rainbow-coloured circles around bright lights" as a sign of sudden glaucoma. Halos are a symptom, not a disease: they tell you that light is being bent, scattered or blocked somewhere on its way to the retina.
Halos usually come with two close relatives. It helps to know the difference, because you will use these words when you describe your symptoms to a doctor:
| Term | What you see | Typical situation |
|---|---|---|
| Halo | A ring or soft glow around a light | Night driving, street lamps, signs |
| Glare | A dazzle that makes a light hard to look at | Oncoming headlights, low winter sun |
| Starburst | Rays or spikes spreading out from a light | Headlights, candles, brake lights |
All three are most noticeable in the dark, because your pupil is at its widest and more light reaches the edges of the cornea and lens, where small irregularities matter most.
What causes halos around lights?
Halos have many causes, from harmless to urgent. In most adults the cause sits in one of three places: the tear film on the surface, the cornea, or the lens inside the eye. The table below lists the main causes, with what else you may notice.
| Cause | Where the problem is | What else you may notice | How urgent |
|---|---|---|---|
| Cataract | Lens clouds with age | Blurry vision, faded colours, trouble seeing at night, frequent glasses changes | See an optician or eye doctor soon |
| Dry eye | Uneven tear film | Gritty, burning or watery eyes; vision that clears when you blink | Routine appointment |
| Changing prescription | Light not focused exactly on the retina | Blur, eye strain, squinting | Eye test |
| After laser eye surgery (LASIK, SMILE, PRK) | Healing cornea, dry eye, small optical imperfections | New symptoms in the first weeks | Tell your surgeon; usually settles over months |
| Multifocal or trifocal lens implant | Rings built into the lens to give near and far focus | Halos around lights at night | Expected to some degree; review if troublesome |
| Clouding behind a lens implant (posterior capsule opacification) | Membrane behind the implant | Blur and glare months or years after cataract surgery | Eye review; short laser treatment |
| Keratoconus | Cone-shaped, distorted cornea | Distorted vision, light and glare sensitivity, frequent prescription changes | See a cornea specialist |
| Acute angle-closure glaucoma | Sudden rise in eye pressure | Severe pain, red eye, headache, nausea | Emergency, same day |
Is seeing halos around lights a sign of cataracts?
Often, yes. The NHS lists halos, light sensitivity, blurred vision and difficulty seeing at night among the symptoms of cataracts, and the American Academy of Ophthalmology (AAO) notes that people with cataracts can be bothered by vehicle headlights at night. Cataracts develop gradually, may affect each eye differently and become more common with age: according to the National Eye Institute (NEI), more than half of Americans aged 80 or older either have cataracts or have had surgery to remove them. The NHS notes that risk rises over 60 and with diabetes, smoking, long-term steroid use and eye injury. The AAO says cataracts can be removed only with surgery; in the early stages an updated glasses prescription may be enough.
Can dry eye cause halos?
Yes. A healthy tear film is a smooth optical surface. When it breaks up, light scatters and rings or blur can appear, often changing from one blink to the next. A 2026 case series of people unhappy after multifocal and trifocal lens surgery lists dry eye among the main causes, and EyeWiki, the AAO's clinical encyclopedia, names dry eye as a contributor to visual symptoms after LASIK. Treating the tear film is therefore the first step before anything more invasive is considered.
Why are halos worse at night?
In dim light your pupil widens. Light then passes through the outer part of your cornea and lens, which is where scars, swelling, cloudiness and lens rings cause the most scatter. EyeWiki links halos after laser surgery to a large pupil in the dark relative to the treated zone of the cornea. This is why halos are often first noticed while driving after dark, and why a normal daytime eye test can miss them.
When are halos an emergency?
Halos with severe eye pain, a red eye, headache, nausea or vomiting need urgent medical care the same day. These are the typical signs of acute angle-closure glaucoma, in which the eye's fluid drainage angle closes and the pressure rises suddenly.
- The AAO lists rainbow-coloured rings or halos around lights, severe eye pain, nausea and vomiting as symptoms, and calls it a true eye emergency that can lead to blindness if not treated right away.
- The NHS lists intense eye pain, a red eye, rainbow-coloured circles around lights, blurred vision, nausea and vomiting and a headache, and advises calling 999 or going to A&E if glaucoma symptoms start suddenly. It says not to drive yourself: ask someone else to drive you or call an ambulance.
- If you are travelling, use the local emergency number or go to the nearest emergency eye service.
The NHS notes that other conditions, including uveitis (inflammation inside the eye) and eye injuries, can cause similar symptoms, which is another reason not to wait. Chronic (open-angle) glaucoma is different: the NEI says it usually has no symptoms at first, and half of people with glaucoma do not know they have it. That is why a regular eye check matters even when you see no halos.
Also see a doctor promptly if the halos are new and you cannot explain them, appear in one eye only, come with a sudden drop in vision, or appear after eye surgery together with pain or worsening vision.
Halos after cataract surgery or with multifocal and trifocal lenses
Cataract surgery usually removes halos that were caused by the cataract itself, but the lens you choose can add its own. A standard monofocal lens focuses at one distance. A multifocal or trifocal lens splits light between near, intermediate and far focus, and that is how it frees many people from reading glasses.
Do multifocal and trifocal lenses cause halos?
They can. A 2025 overview of eight systematic reviews in the British Journal of Ophthalmology found that multifocal lenses give better spectacle independence but cause more glare and halos, and that trifocal and extended-depth-of-focus lenses give better intermediate vision. A 2026 review of trifocal lenses reaches a similar conclusion: trifocals may give stronger near performance and spectacle independence, although halos may occur. This is a trade-off, not a fault: you gain focus at several distances and may accept some rings around night-time lights.
| Monofocal lens | Trifocal or multifocal lens | |
|---|---|---|
| Distance vision | Sharp | Sharp |
| Reading without glasses | Usually needs glasses | Often possible |
| Halos and glare at night | Fewer | More likely |
| Needs a healthy surface and cornea | Yes | Yes, and any problem matters more |
Why do some people dislike their new lens?
A 2026 review, "When trifocal IOLs disappoint", lists the causes of dissatisfaction as residual glasses prescription, light-related phenomena, dry eye, difficulty adapting, and a tilted, off-centre or clouded lens implant. A 2026 case series of 307 patients with presbyopia-correcting lenses found that the main causes were residual refractive error, dry eye disease and posterior capsule opacification, and that treating those causes improved symptoms in most eyes. A further study found that the measured size of halos around lights falls after lens surgery, although what people report can lag behind it, so patience and a proper check-up both matter.
What this means for you: before surgery, your surgeon should check the tear film, the cornea, the retina and your pupil size, treat anything that can be treated, and tell you honestly whether a multifocal lens suits you. If crisp night vision matters most to you, for example because you drive a lot after dark, say so at your consultation so that your surgeon can discuss the other lens options with you.
At Laser Istanbul Clinic, premium-lens and trifocal surgery is led by Prof. Dr. Ahmet Satıcı; cataract surgery is also performed by Doç. Dr. Muhammet Derda Özer (Doç. = Associate Professor) and Op. Dr. Aysan Bayram. Surgery takes place in a fully equipped, Ministry of Health–licensed operating theatre in Istanbul.
What about clouding months or years after cataract surgery?
Sometimes the thin membrane that holds the lens implant becomes cloudy. This is called posterior capsule opacification (PCO). EyeWiki reports that it occurs in around 20 to 50 percent of patients within 2 to 5 years after cataract surgery, and its symptoms include blurred vision, glare and halos around lights. It is treated with a non-invasive laser procedure called Nd:YAG laser capsulotomy, which opens the clouded membrane. If your halos return after a period of clear vision, this is a likely cause and can be checked at an eye examination.
Halos after laser eye surgery (LASIK, SMILE, PRK)
Halos, glare and starbursts are among the best-known short-term side effects of laser vision correction. In the US PROWL studies of 534 LASIK patients, 43–46% reported a new visual symptom (halos, glare, starbursts or double vision) 3 months after surgery, yet only 1–4% were dissatisfied with their vision. EyeWiki says about 20% of patients notice some visual change and that most disturbances settle within 3 to 6 months. The US Food and Drug Administration (FDA) notes that some patients develop glare, halos or double vision that can seriously affect night vision, and that some see less well in low contrast, such as at night or in fog.
EyeWiki lists the usual causes: higher-order optical imperfections from creating the flap (especially spherical aberration and coma), a pupil that opens wider in the dark than the treated zone, a small treatment zone, off-centre treatment and dry eye. Management includes time, treatment of dry eye, pupil-constricting drops (pilocarpine or brimonidine), wavefront-guided or topography-guided enhancement for persistent cases, and specialty contact lenses for the rare eye that does not improve. If halos are still bothering you months after laser surgery, tell your surgeon rather than waiting.
How are halos diagnosed and treated?
Treatment follows the cause, so the first step is always a proper eye examination. Expect these steps:
- Your story. When the halos started, one eye or both, only at night, any pain, previous eye surgery, medicines.
- Vision and prescription check. A changed prescription is one of the simplest causes to fix.
- Surface and tear-film check. To look for dry eye and corneal problems.
- Dilated examination. The NEI calls this the best thing you can do for your eye health. Drops widen your pupils so the doctor can see inside the eye; your vision may be blurry and light-sensitive for a few hours, so bring sunglasses and arrange for someone else to drive you home.
- Pressure measurement and corneal scans where needed. To check for glaucoma and for conditions such as keratoconus.
| Cause | Typical treatment |
|---|---|
| Cataract | Surgery to replace the clouded lens with an artificial lens, once symptoms interfere with daily life; the NEI says 9 out of 10 people see better afterwards |
| Dry eye | Lubricating drops and lid care, then prescription treatment if needed |
| Prescription change | New glasses or contact lenses |
| After laser surgery | Time, dry-eye treatment, pupil-constricting drops, or enhancement in selected cases |
| Multifocal or trifocal lens | Treat dry eye and any residual prescription, check lens position, laser for clouding; reviewed individually |
| Posterior capsule opacification | Nd:YAG laser capsulotomy |
| Acute angle-closure glaucoma | Emergency treatment to lower eye pressure |
What can you do about night-time halos in the meantime?
- Book an eye test. New halos deserve a check even if they seem mild.
- Be careful with night driving. If halos or glare make headlights hard to look at, avoid driving after dark until you have been examined.
- Keep your glasses up to date. An out-of-date prescription makes lights look worse.
- Look after your tear film. Take screen breaks, blink fully and avoid smoke and dry, windy air, as the NEI advises for dry eyes.
- Protect your eyes in the sun. The NHS lists long-term sun exposure without eye protection as a cataract risk factor.
- Do not ignore other eye symptoms. Twitching, flashes, floaters and blur each have their own causes. See our guide on eye twitching: causes, when to worry and how to stop it.
Frequently asked questions
The most common causes are cataracts, dry eye, a changed glasses prescription, healing after laser eye surgery and multifocal or trifocal lens implants. In the dark your pupil widens, so light passes through the edges of the cornea and lens, where irregularities scatter it into rings. An eye examination finds which cause applies to you.
Usually they are not dangerous, but they should always be checked. They are an emergency when they come with severe eye pain, a red eye, headache, nausea or vomiting, which can mean acute angle-closure glaucoma. In that case go to emergency care the same day.
It can be. The NHS lists halos and difficulty seeing at night among cataract symptoms. Cataracts also cause blurred vision, faded colours and glare. Only an eye examination can confirm whether a cataract is the cause, and surgery is the only way to remove one.
For most people, yes. EyeWiki reports that visual disturbances such as halos usually settle within 3 to 6 months as the cornea heals and dry eye improves. A small number of people have longer-lasting symptoms, and options such as pupil-constricting drops or an enhancement exist if so.
They can cause more halos and glare than other lens types, according to a 2025 overview of systematic reviews, in exchange for better reading and intermediate vision without glasses. How much they bother you depends on your eyes, the lens and how well you adapt. Your surgeon should discuss this with you before choosing a lens.
Often, because treatment depends on the cause: new glasses for a prescription change, drops for dry eye, laser for clouding behind a lens implant, surgery for a cataract. Halos that come from the design of a multifocal lens may be reduced but not always removed, which is why choosing the lens carefully matters.
Halos in one eye can come from a cataract developing in that eye, a tear-film problem, a corneal irregularity or sometimes a more serious cause. Because it can point to a local problem, sudden one-eye halos should be examined promptly, and straight away if you have pain or reduced vision.
Start with an optician or an ophthalmologist. For cataract or lens questions, an ophthalmologist who performs lens surgery is the right specialist; for corneal problems such as keratoconus, a cornea specialist. At Laser Istanbul Clinic, Prof. Dr. Ahmet Satıcı and Doç. Dr. Muhammet Derda Özer cover lens and cornea, and Op. Dr. Aysan Bayram performs cataract surgery.
Seeing halos and thinking about a new lens?
Send your prescription and any scans for a free online consultation. Your surgeon will tell you whether your halos point to a cataract or another cause, and honestly whether a trifocal lens, another lens type or no surgery suits your eyes. Premium-lens surgery is led by Prof. Dr. Ahmet Satıcı.
Sources for the facts on this page
- All pages below were opened and checked on 7 Oct 2026.
- NHS. Cataracts. https://www.nhs.uk/conditions/cataracts/
- NHS. Glaucoma. https://www.nhs.uk/conditions/glaucoma/
- American Academy of Ophthalmology. What Is Glaucoma? https://www.aao.org/eye-health/diseases/what-is-glaucoma
- American Academy of Ophthalmology. What Are Cataracts? https://www.aao.org/eye-health/diseases/what-are-cataracts
- American Academy of Ophthalmology. What Is Keratoconus? https://www.aao.org/eye-health/diseases/what-is-keratoconus
- National Eye Institute (NIH). Cataracts. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/cataracts
- National Eye Institute (NIH). Glaucoma. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma
- National Eye Institute (NIH). Get a dilated eye exam. https://www.nei.nih.gov/learn-about-eye-health/healthy-vision/get-dilated-eye-exam
- EyeWiki (AAO). LASIK Complications. https://eyewiki.org/LASIK_Complications
- EyeWiki (AAO). Posterior Capsule Opacification. https://eyewiki.org/Posterior_Capsule_Opacification
- American Academy of Ophthalmology, EyeNet. Postoperative Symptoms and Satisfaction With LASIK Surgery (summary of the PROWL studies). https://www.aao.org/eyenet/article/postoperative-symptoms-satisfaction-with-lasik-sur
- US Food and Drug Administration. LASIK: What are the risks and how can I find the right doctor for me? https://www.fda.gov/medical-devices/lasik/what-are-risks-and-how-can-i-find-right-doctor-me
- Daka Q, et al. Effectiveness of intraocular lenses designed to correct presbyopia after cataract surgery: an overview of systematic reviews. British Journal of Ophthalmology 2025. https://doi.org/10.1136/bjo-2025-327363
- Khorrami-Nejad M, et al. When trifocal IOLs disappoint: diagnostic and management pathway. Therapeutic Advances in Ophthalmology 2026. https://doi.org/10.1177/25158414261471349
- Wang K, et al. Reasons for dissatisfaction after implantation of extended depth-of-focus and trifocal intraocular lenses: a retrospective case series. BMC Ophthalmology 2026. https://doi.org/10.1186/s12886-026-04703-1
- Bhogal-Bhamra GK, et al. Glare prediction and mechanism of adaptation following implantation of hydrophilic and hydrophobic intraocular lenses. Frontiers in Ophthalmology 2024. https://europepmc.org/article/MED/38984113 (abstracts for sources 13–16 read via Europe PMC)