Light is crucial for our vision. We see objects around us when light bounces off them and enters our eyes. But sometimes, light can be the cause of vision problems when it causes halos or glare.
Halos are bright circles that appear to surround a source of light, such as oncoming car headlights. Glare is light that enters your eye but doesn't help you see better. Rather, it interferes with your vision.
Glare can be:
Uncomfortable. When you're trying to see in the presence of a too-bright light, you may squint and try to look away from the light. Your eyes may become teary.
Disabling. Glare can sometimes impair your vision. Light is scattered within the eye and reduces the contrast of images. The loss of contrast is often worse with disabling glare in dim lighting as opposed to bright environments.
Halos typically occur when your surroundings are mostly dim or dark. Glare is more likely in the daytime.
Halos and glare may be caused by an eye problem, but can also be a normal response to bright lights.
Causes of halos and glare include:
Cataracts. Halos are a common symptom of cataracts. So is glare, giving you the sense that normal lights are too bright.
Normally, the lens at the front of your eye is clear, allowing light to pass as easily as through a window. A cataract causes the lens to grow cloudy. This makes your vision blurry and affects the way you see light.
Common eye problems. Eye problems that keep the eye from properly focusing light onto your retina can also cause halos and glare. Your retina is the thin lining in the back of the eye. It plays a crucial role in vision.
Common eye problems that can cause halos and glare include:
Nearsightedness (hard to see things that are far away, often worse at night)
Farsightedness (hard to see things nearby due to the natural shape of your eyeball)
Presbyopia (hard to see things nearby due to aging)
Astigmatism (blurred vision due to irregular shape of the cornea -- the front surface of the eye)