​​What are Halos around lights?


Seeing haloes around lights is a symptom where colored or luminous rings are seen around lights such as street lights or other light sources.


Haloes around bright lights tend to be especially worse when driving at night and can interfere with vision and are hence, potentially dangerous. They are commonly associated with glare, a symptom characterized by difficulty looking at bright light as it hurts the eyes, resulting in blurring of vision and tearing.

These symptoms are more common in older people, and in those who have had certain types of refractive surgery or who have certain types of cataracts. Haloes can also occur in people with dry eyes or people whose pupils are widely dilated (for example, those who have been given eye drops for an eye examination).

The appearance of a huge, perfectly circular halo round the Sun in Mexico in 2015 sparked rumours of the impending end of the world. In reality, it was the product of sunlight being refracted through hexagonal ice crystals high in the atmosphere. Water droplets can do the same, producing a smaller, more colorful halo.

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