Rainbow halos around lights can be harmless or signal serious eye pressure or corneal problems.
Less serious causes
Mild halos may occur with dry eye, dirty lenses, or early cataract. The effect often improves with blinking or cleaning.
- Smearing on glasses or contact lenses
- Early lens clouding causing light scatter
- Minor corneal swelling from over-wear of contact lenses
- Temporary glare after bright light exposure
Serious causes needing urgent care
Acute angle-closure glaucoma can cause intense pain and coloured haloes. This is an emergency needing immediate treatment.
- Haloes with severe eye pain, headache, and nausea
- Blurred vision and a hard, tender eye
- Redness and seeing rings around lights at night
- Emergency hospital assessment is essential to save sight
