Do you often see bright rings or ‘halos’ around lights, particularly at night or in dimly-lit rooms? It happens to everyone from time to time – but if you constantly see halos around lights, it could indicate a serious vision problem.

Here’s what you need to know.

Seeing Halos: Why It Happens

Fundamentally, the halos are caused by a diffraction effect, which means the light bends after it enters your eye. This causes your eyes to have trouble focusing properly, creating the illusion of rings around the light source.

Sometimes, this just happens naturally. If you’re in a dark space and are suddenly hit with a bright light, your pupils go from fully dilated (open) to slamming shut as quickly as possible. This rapid change in pupil size can cause a halo to occur.

However, this should only happen occasionally, if you’re hit with sudden bright light. If you’re constantly seeing halos, that’s a problem which should be checked out by eye care professionals.

Vision Problems That Can Cause Halos

There are several different conditions that can potentially cause halos.

Dry eyes
Dry eyes can become inflamed, which slightly alters the shape of your eye. In addition, the dryness can already cause blurry vision. If your eyes are itchy when halos happen, try eye drops.

Photokeratitis is basically a sunburn on your eyes, caused by too much UV exposure, such as “snow blindness.” Halos are one symptom. Fortunately, photokeratitis should go away on its own after a couple days. Just wear sunglasses until your eyes heal.

Many migraine sufferers experience visual distortions along with the migraine. Halos are potentially one of those distortions, but should go away when the migraine ends.

Halos are one of the early warning signs that cataracts are developing. Cataracts are cloudy areas on the eye that slowly expand to cover the entire outer surface. The elderly are most prone to cataracts, but almost anyone can potentially start developing them.

Glaucoma is a condition where the eye is deformed by high pressure inside the eyeball. Left unchecked, it can damage the optic nerve, and potentially lead to full blindness in that eye. Halos are also an early warning sign for glaucoma.

In short, if you frequently see halos around lights at night, or in dim rooms, you need to have it checked out. Contact Valley Eyecare Center in Phoenix for an appointment and check-up!