Many of us have experienced seeing halos around lights, whether on a night-time walk or driving in the rain. But is this normal? And, above all, when should we be concerned?
What are halos around lights?
Halos are circles of light that appear around a light source, such as car headlights or streetlamps. They can vary in size and intensity and are often more visible in low-light conditions, such as at night. This phenomenon is due to the diffusion or refraction of light by the various structures of the eye, notably the cornea and crystalline lens.
Benign causes
In some situations, seeing halos is perfectly normal. Here are a few examples of common, benign causes:
- Environmental conditions: Halos can appear when light is scattered by humidity, rain, fog, or other particles in the air.
- Eye fatigue: After long hours of reading or working on a screen, your eyes can become tired, leading to impaired vision, including halos.
- Dirty or ill-fitting glasses or contact lenses: Poorly cleaned or damaged lenses can affect light entering your eyes, creating halos.
- Post-operative effects: After eye surgery, including laser surgery or intraocular lens implantation, it's common to see halos around lights during recovery.
When to be concerned
Seeing halos can sometimes indicate a medical condition requiring special attention. Here are a few cases where it's important to consult a medical professional:
- Cataracts: Cataracts are an opacification of the crystalline lens that can cause halos around lights, especially at night. They are common in older people but can also occur earlier in some people.
- Glaucoma: Glaucoma is a disease that affects the optic nerve and can lead to high intraocular pressure. A common symptom of glaucoma is seeing coloured halos, often accompanied by eye pain or headaches.
- Keratoconus: This condition affects the cornea, making it thinner and more conical, which disturbs vision and can cause halos and distorted images.
- Corneal edema: Swelling of the cornea can also cause halos and is often associated with other symptoms such as pain and sensitivity to light.
- Severe dry eye: When the eyes don't produce enough tears, this can lead to blurred vision and halos, especially in low-light conditions.
What to do if you see halos?
If you regularly see halos around lights and they become bothersome, you should make an appointment with an Optometrist. An Optometrist can assess whether the halos are related to a serious eye condition or simply a temporary factor.
Seeing halos around lights can sometimes be normal, especially after a long day or within certain environmental conditions. However, if this phenomenon becomes recurrent or is accompanied by other symptoms, it's important to consult an Optometrist to rule out any serious eye condition. By taking good care of your eyes and monitoring changes in your vision, you can ensure better long-term visual health.
