There are some common reasons for seeing these colourful lights in your line of vision. Halos noticed around lights at night-time are commonly seen by people recovering from recent laser vision correction or by myopic, or nearsighted, people who are not wearing their proper prescription eyewear.
Halos with rainbows can also sometimes indicate a more serious problem. These could include: cataracts, swelling of the lens in the eye due to diabetes, a foreign body in the cornea, or possibly glaucoma. Book an appointment with your doctor of optometry immediately if you experience these symptoms. Most optometrists hold emergency appointments in their schedules and will be able to see you on the same day.
In addition to seeing rainbows and halos, if you also experience sudden blurred vision with eye pain, seek immediate medical attention or visit your optometrist. This can be an indicator of an episode of glaucoma, which could cause blindness if not treated. It is recommended to see you optometrist immediately should these symptoms occur.