---
title: "Halos around lights | Eye Health Guide"
description: "What causes halos and glare around lights at night, from cataracts to acute glaucoma, and the warning signs that need emergency care. Clinically reviewed."
url: https://eyehealthguide.org/symptoms/halos-around-lights/
source: Eye Health Guide
licence: "General information only. Cite the URL and the named medical reviewer."
---

Symptom

# Halos around lights

Sudden painful halos are an emergency

Medical reviewer [Mr Mohamed Mohyudin](https://eyehealthguide.org/reviewers/mohamed-mohyudin/)· Last recorded site review July 6, 2026

### About this review

This page inherits the site’s previous review record. A separate, current article sign-off has not yet been recorded.

[How review works](https://eyehealthguide.org/reviewers/) · [Official biography & credentials](https://mohamedmohyudin.co.uk/author/mohamed-mohyudin/)

Quick answer

Halos around lights are most often caused by cataracts or refractive problems and are usually not an emergency. However, sudden halos with a painful red eye, headache and nausea can signal acute glaucoma, which is a medical emergency needing immediate care.

## When to get urgent help

- Sudden halos with a painful, red eye
- Halos with a headache, nausea or vomiting
- Halos with sudden blurring or loss of vision
- Halos soon after eye surgery with pain or redness

### On this page ⌄

1. When to get urgent help
2. Common causes
3. What can help
4. Frequently asked questions

## Common causes

Halos come from light scattering as it passes through the eye. These are common reasons.

## What can help

- Book an eye test, as cataracts and focusing problems are common causes
- Treat sudden painful halos with nausea as an emergency
- Take care driving at night if glare affects your vision

## Frequently asked questions

### What causes halos around lights at night?

The most common cause is cataracts, along with refractive problems such as astigmatism. Sudden halos with eye pain and nausea can signal acute glaucoma and need emergency care.

### Are halos around lights serious?

Usually not, when they come on gradually with cataracts. But sudden halos with a painful red eye, headache or nausea are an emergency and need immediate care.

### Can glasses or surgery help halos?

Yes. Updating your glasses can reduce halos from focusing problems, and cataract surgery often removes halos caused by a cloudy lens.

Your next step

## Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

## Trusted sources

For general background, these organisations provide eye-health information. This list is further reading, not a record that they reviewed this article.

- [NHS — Health A to Z](https://www.nhs.uk/conditions/)
- [Moorfields Eye Hospital NHS Foundation Trust](https://www.moorfields.nhs.uk/)
- [American Academy of Ophthalmology — EyeHealth](https://www.aao.org/eye-health)
- [National Eye Institute (NIH)](https://www.nei.nih.gov/)
- [College of Optometrists — Look After Your Eyes](https://lookafteryoureyes.org/)
- [World Health Organization — Eye care, vision impairment and blindness](https://www.who.int/health-topics/blindness-and-vision-loss)