Glare and Halos After Cataract Surgery: Preventable, Fixable, and Often Misdiagnosed

Published: 15 Sep 2026

A little glow or a faint ring around lights after cataract surgery can be completely normal, and it can happen with almost any type of lens. But when glare and halos start to change the way you live — when you avoid driving at night, feel unsafe with oncoming headlights, or struggle in certain rooms and lighting — that's no longer "just normal." That's a problem with a real, findable cause, and usually, a real solution.

Dr. Ilan Cohen, a cataract and premium lens surgeon in New York with 25 years of experience, has developed a structured way to diagnose and treat glare and halos after cataract surgery. Below, he breaks down that approach in plain language — including the questions worth asking before surgery, and the ones worth asking if you're already dealing with this problem now.

It's Not "Just in Your Head" — It's Physics

If every light at night looks like it's exploding, you're not being too picky. You're noticing something real. The question is where the light is being distorted.

Think of the eye like a camera. The clear front window of the eye — the cornea — is like the front glass of the camera. The artificial lens placed during cataract surgery is like the lens inside the camera body. Normally, the eye focuses light into a single sharp point on the retina. Glare and halos happen when that light gets scattered instead — showing up as rings, starbursts, or a fuzzy glow, especially with:

• Night driving
• Headlights coming toward you
• Streetlights
• Bright signs or screens in a dim room

If the front window is a little warped, or the internal lens doesn't quite match the eye, light scatters instead of focusing cleanly. The critical step is figuring out which part is causing the trouble — the window, the lens, or both — before adding more lasers or more drops. Skip that step, and it's easy to bounce from one procedure to the next without ever fixing the real cause.

Where These Problems Actually Start: The Pre-Surgery Setup

A lot of glare and halo problems are set up before surgery ever happens, in the lens-planning phase. Not every eye is a good match for every type of premium lens — and some corneas simply aren't ideal partners for multifocal designs. Here are the red flags Dr. Cohen looks for carefully before recommending a multifocal lens:

• Prior LASIK, PRK, or RK. These corneas have already been reshaped. They can see very well, but the optics are often a bit more irregular at night. Some do fine with multifocal lenses; others are far more sensitive to glare and halos.
• Corneal scars. A scar scatters light on its own. Add a multifocal lens that already splits light into different focal points, and you're layering scattered light on top of split light — a combination prone to halos and starbursts.
• ABMD (anterior basement membrane dystrophy). The surface layer of the cornea isn't perfectly smooth. That disrupts the tear film and makes the optics "noisy," especially in low light.
• Salzmann's nodular degeneration. Raised nodules distort the smooth curve of the cornea, creating local areas of distortion and scatter.

When any of these show up before surgery, Dr. Cohen doesn't move straight to a standard diffractive multifocal lens and hope for the best. He either adjusts the lens choice — often toward a monofocal or a non-diffractive extended depth-of-focus lens, which tends to be gentler on the optics — or has a direct conversation with the patient about the higher risk involved. Many glare and halo problems, in other words, aren't random. They're the result of a mismatch between a sensitive cornea and a complex lens design.

Already Had Surgery? Start With Diagnosis, Not Another Procedure

If that pre-op conversation never happened and you already have the glare, the fix isn't to guess your way through more treatments. Dr. Cohen's post-op protocol starts with one question: is the cornea — the front window — the main culprit?

To find out, he uses a hard contact lens test in the office. A hard contact lens has a smooth, perfectly round front surface. Placed on the eye, it covers over small bumps and irregularities on the cornea, effectively forcing an irregular cornea to behave like a regular one.

Here's how it works: the lens goes on, the room is dimmed, and the patient looks at different lights from different angles — comparing what they see with and without the lens in place.

• Symptoms improve clearly with the lens on: a positive test. The cornea is playing a major role.
• Nothing changes, or only minimally: the problem more likely lies with the internal lens implant.

It's a functional test rather than just numbers and maps — it asks how a patient actually sees when the front surface is temporarily smoothed. That result determines everything that follows.

If the Cornea Is the Problem: Topography-Guided PRK (TGPRK)

When the hard contact lens test is clearly positive, the next question is whether the real cornea can be made to behave more like that smooth lens — permanently, without wearing a hard contact lens forever. For many patients, the answer is topography-guided PRK, or TGPRK.

PRK is a laser treatment on the surface of the eye. "Topography-guided" means the laser isn't just correcting a basic glasses prescription — it's working from a detailed map of the cornea's hills and valleys, programmed to smooth out those irregularities using a protocol Dr. Cohen has adopted and modified for this specific purpose.

The goal isn't just "20/20 on the chart." It's a smoother window that scatters less light, so the existing intraocular lens — even a multifocal one — can work inside a cleaner optical system. Patients often notice less glow around lights, smaller halos, and calmer, more stable night driving.

TGPRK isn't right for every eye — corneal thickness, topography, healing tendencies, and overall eye health all factor in. But in Dr. Cohen's experience, it helps in about 80% of cases involving blurred vision, glare, or halos after cataract surgery. That lines up with a Harvard study that used TGPRK (without the hard contact lens test) and saw improvement in 23 of 28 patients.

If the Lens Is the Problem: IOL Exchange

If the hard contact lens test does almost nothing for the symptoms, polishing the window won't help — attention turns to the intraocular lens (IOL) itself, the artificial lens that replaced the cataract.

In these cases, one option is an IOL exchange: going back in, removing the current implant, and replacing it with a better match. Reasons this might be necessary include:

• A lens design the eye simply doesn't tolerate well
• A lens that is decentered or tilted
• A lens power that leaves an unexpected prescription, worsening visual quality

An IOL exchange is only recommended after the cornea has been properly ruled out as the main driver — no one should go through another surgery unless the lens truly looks like the limiting factor. It's also a more complex procedure than the original cataract surgery and should be performed by someone experienced specifically with lens exchanges. Done for the right reason, though, it can make a major difference in glare and halos.

The YAG Capsulotomy Trap — Why Timing Matters

There's one more piece that can make this process easier or much harder: the YAG capsulotomy, a laser procedure many patients eventually need after cataract surgery. Over time, the thin membrane behind the implant — the posterior capsule — can become cloudy and blur vision. A YAG laser opens that membrane so light passes through clearly again, and when that membrane truly is the problem, it's an excellent, simple fix.

But when glare and halos are still a mystery, doing a YAG "just to see if it helps" can backfire. Once the membrane is opened, the lens loses some of its support from behind — and if a lens exchange turns out to be necessary later, the surgery becomes more technically challenging and riskier. In Dr. Cohen's protocol, YAG is never the first move when the cause is unclear. It comes only after a clear diagnosis and plan:

• Evaluate the cornea carefully
• Perform the hard contact lens test under real-world conditions
• If the cornea is the culprit, address it — often with TGPRK
• If the lens is the culprit, consider a lens exchange
• Only once the posterior capsule is confirmed as the cause, move to a YAG capsulotomy

Skip that sequence, and it's easy to close doors that might be needed later.

What to Ask, Depending on Where You Are

If you haven't had cataract surgery yet and are considering a multifocal lens, ask your surgeon:

"Is my cornea a good partner for this lens?"

Ask specifically about prior LASIK, PRK, or RK; corneal scars; ABMD; or Salzmann's nodules — and how those conditions affect the risk of glare and halos with a multifocal design. Ask, too, whether a different lens type, such as a monofocal or a non-diffractive extended depth-of-focus lens, might offer more reliable quality of vision for your eyes specifically.

If you already had surgery and are dealing with glare and halos now, ask whether your doctor has experience with, or is comfortable performing, a hard contact lens test — it's not a test every surgeon runs routinely, and a lot rides on getting the result right. You never want to push a doctor into a test they aren't confident performing.

"If the hard contact lens test shows my cornea is irregular and my symptoms improve with the lens, is a topography-guided treatment like TGPRK an option for me?"

And before agreeing to any YAG laser, ask directly:

"If this YAG doesn't help, will it make a future lens exchange harder or riskier?"

You deserve clear, honest answers — and a surgeon who understands both the cornea side and the lens side of the problem, not just someone reading a few numbers off a chart. Choose based on experience, attention to detail, and whether there's a logical, step-by-step plan built around your specific eye.

Bringing It All Together

Glare and halos after cataract surgery are usually not "just in your head," and they aren't an automatic price to pay for surgery. They typically trace back to something specific and fixable — either in the front window of the eye, in the lens implant, or in a mismatch between the two.

A structured approach — careful pre-op screening, thoughtful lens selection, post-op hard contact lens testing, TGPRK when the cornea is the culprit, and IOL exchange when the lens is the culprit — helps most patients get to the comfortable vision they expected in the first place.

Wanting to see well after cataract surgery isn't asking for too much. This is your vision for the rest of your life, and most problems with it have a clear, findable cause.

Struggling with glare, halos, or blurry vision after cataract surgery? You don't have to keep guessing your way through it. Schedule a consultation with Cohen Eye Institute to get a clear diagnosis — cornea, lens, or both — and a real plan to fix it.