What causes halos after LASIK?

You’re not going to be walking around with a glowing ring floating over your head, but after having Laser Eye Surgery you are likely to experience another type of halo.

Halos are a form of glare that temporarily affects vision after Laser Eye Surgery. They occur mainly at night and in low light conditions, appearing as bright circles around light sources such as headlights or a street lamps.

Not so much a side effect in the most common sense of the word — an unintended and often seemingly unrelated consequence of a medication, drug, or surgery — halos are a healthy sign the eye has begun its recovery process, accumulating beneficial fluid in the cornea in the form of swelling.

As a part of the eye’s natural recovery process, every patient who has Laser Eye Surgery can expect to encounter glare — regardless of age, prescription, technique, or individual profile. Other than halos, glare can manifest in the form of starbursts, which, rather than being a ring around lights, appear more like a dispersed glow.

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The extent to which this affects a patient’s life is minor. It’s common for patients not to notice glare like starbursts and halos at all, while even those who do may simply avoid doing any significant amount of night driving for a few weeks.


Mr Glenn Carp explains the effect of night glare after Laser Eye Surgery.

In these first few weeks after Laser Eye Surgery, patients may also experience minor fluctuations in quality of vision as it stabilises and also dry eyes (for which clinics provide lubricated eye drops). In the vast majority of cases, all of these things are mild and gradually disappear over the first few days or weeks.

After around the three-month mark, swelling in the cornea will have settled along with any visual disturbances. Regarding halos, it’s not uncommon to have a little residual night glare after this time. But if it’s severely disrupting your vision, it’s a good idea to visit your clinic for further testing. There a surgeon can identify the source of the issue and see if there’s a problem that needs to be addressed.

Prolonged night glare is most often the result of under or overcorrection due to a poor pre-operative assessment. This is the stage where all the tests and measurements on your eyes are carried out, your individual treatment plan drawn up, and your suitability for surgery is determined.

At a high-quality clinic that provides a thorough and accurate assessment, patients are only eligible for treatment if they meet strict requirements. If there were any concerns over the standard of vision you could reach, you would be made aware of the fact and/or be disqualified.

If you’ve already had Laser Eye Surgery and are experiencing night glare long after the three-month period, it could be the result of a number of things. For instance, the laser may not have shaped the eye enough during the procedure and therefore you may still be slightly short or long-sighted and/or still have a minor astigmatism. Another possibility is that the size of the pupil wasn’t properly measured in testing and therefore you glare and halos appear in low light conditions.

If this sounds familiar, the course of action is relatively straightforward — with many patients benefitting from having a simple follow-up procedure or wearing glasses at night.

Again, these scenarios are extremely unlikely given a thorough screening process — something we at London Vision Clinic are particularly known for.

Contact us today to find out more about our screening process or to book your consultation. 

What causes halos after LASIK?

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