Halos, Glare and Starbursts After Cataract Surgery

If you're researching IOL options — or you've already had surgery and you're staring at streetlights wondering if this is permanent — you've probably run into the word dysphotopsia. It's the umbrella term for the unwanted visual effects some patients see around light sources at night: halos, glare, and starbursts. I get more questions about this topic than almost any other, so let's go through it properly: how common it really is, why the numbers you read online are all over the place, what causes it, and — most importantly — what you can actually do about it.

It's not just an IOL problem

Here's something that surprises most people: night dysphotopsias aren't exclusive to intraocular lenses. Healthy, phakic (natural-lens) eyes experience them too. I have significant hyperopia and astigmatism myself, and when I'm not wearing correction, I see a starburst pattern around lights at night. My wife is moderately myopic, and she sees halos instead. Cataracts, dry eye, and uncorrected refractive errors like myopia, hyperopia, or astigmatism can all produce these effects on their own. So when a patient reports halos after implant surgery, the first question isn't "which lens did they get" — it's "is this even coming from the lens."

That said, once we're specifically talking about IOLs, there are three recognizable patterns:

• Glare — a general brightening/scattering around a light source
• Halo — a distinct ring around the light
• Starburst — spikes radiating outward from the light source

Diffractive multifocal and full-range designs can produce more halos or starbursts than their monofocal controls. EDOF lenses use different mechanisms and do not all create several separate focal points; their symptom profiles must be checked model by model. But — and this is the part people skip — even the simplest monofocal lens can produce some degree of dysphotopsia in some patients.

One more distinction worth knowing before your surgery, because it comes up in consent forms and consultations: everything above — glare, halo, starburst — falls under what ophthalmology formally calls positive dysphotopsia: unwanted extra light your visual system perceives. There's a separate, less commonly discussed category called negative dysphotopsia — a dark shadow or crescent, usually in your peripheral vision, that some patients notice after IOL surgery. It's a genuinely different phenomenon with a different likely mechanism (related to how light interacts with the edge of the IOL optic rather than how it scatters), and it doesn't respond to the same "wait for neuroadaptation" advice in quite the same way for every patient. If what you're experiencing is a shadow rather than a ring or a burst of light, say that specifically to your surgeon — it changes the conversation.

Why does "how common is it" get such wildly different answers?

If you go looking for one hard percentage, you will find incompatible answers. The exact lens matters, but the measurement method can move the number dramatically.

Two things commonly move it:

1. How the question is asked. A spontaneous report counts only what a patient mentions without prompting. A directed questionnaire names halo, glare or starburst and asks about frequency or bother. Those are different outcomes.
2. How many patients the percentage represents and where the severity threshold was set. “Any halo” is not the same result as “severely bothered by halo,” and neither is the same as a lens exchange.

So when you see a percentage, ask: which model, which question, how severe, how many patients and at what follow-up?

Noticing a halo is different from being troubled by it

How often a symptom is noticed is not the same as how often it is severe. Study numbers vary because questionnaires, lens designs and follow-up periods differ. Persistent symptoms that affect driving or daily life deserve a proper examination; they should not be dismissed because most patients adapt.

Do not predict a symptom from the category name alone

A diffractive full-range lens and a standard monofocal do not have the same symptom profile, but category labels are still too crude for a personal forecast. For example, the FDA trials for PanOptix and Synergy used different questionnaires, so even two percentages from those reviews are not automatically a fair head-to-head comparison.

Use illustrations to learn the difference between a ring, a haze and radiating spikes—not to predict the shape or severity you personally will see.

Where does it actually come from?

We don't have a single clean answer for why one patient gets dysphotopsia and another with the same lens doesn't. But there are recognized contributing factors:

• Corneal irregularities
• Pupil size and pupil abnormalities
• IOL decentration
• Residual prescription error is one treatable contributor worth checking.

And underneath all of that is your visual cortex. Some people notice a stable optical pattern less over time; this is called neuroadaptation. It can help, but it is not a promise and it should not be used to dismiss a symptom before dry eye, residual prescription, IOL position, posterior capsule and retinal causes are checked.

Range and night vision must be checked model by model

A distance-targeted monofocal usually leaves reading and often intermediate work to glasses. A diffractive full-range lens can reduce that dependence, and its pivotal trial may also show more halos or starbursts than the monofocal control. But not every design that adds range shows the same worsening. The claim is only fair when it names the exact lens, the lens it was compared with and what the study measured.

This is why I do not accept “premium lens” as an explanation. Ask what happened with the proposed model, using a symptom questionnaire that separates noticing a phenomenon from being bothered by it.

What actually helps if you're already dealing with it

The first step is to check treatable causes: dry eye, residual prescription error, corneal irregularity, IOL position, posterior capsule opacification and retinal disease. Neuroadaptation can make some optical effects less noticeable over weeks or months, but it is not the only answer. If symptoms are severe, worsening, one-sided, or make driving unsafe, contact your surgeon rather than trying to ignore them.

Before you choose a lens

There is no universally best IOL. The useful question is which trade-off fits your life: maximum distance contrast and night-driving comfort, more intermediate range, or greater independence from reading glasses. IOL exchange is possible in selected cases, but it is another intraocular procedure with additional risk — a reason to clarify priorities before the first surgery.

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