If you’ve ever noticed that streetlights or headlights at night seem to have rays of light shooting out of them, like a starburst, you’re not alone. Many people describe lights as looking streaky, hazy, or surrounded by halos, especially when driving at night.
One of the most common reasons for this phenomenon is astigmatism, an irregularity in the shape of your eye that affects how light is focused. Astigmatism is incredibly common, and the good news is that it’s very treatable.
Let’s break down what astigmatism is, why it causes lights to look the way they do, and how you can find relief.
What Is Astigmatism?
For clear vision, light needs to pass through the front of the eye (the cornea and lens) and focus directly on the retina at the back. If the cornea is perfectly round, like a basketball, light bends evenly and produces a crisp image.
But with astigmatism, the cornea (or sometimes the lens inside the eye) is shaped more like a football — steeper in one direction and flatter in another. This irregular shape bends light unevenly, which means it can’t come to a single sharp focus point.
The result? Vision that looks blurry, stretched, or distorted, and lights that seem to sprout lines or halos.
Why Lights Look Like They Have Lines
Astigmatism doesn’t always affect daytime vision in obvious ways. But at night, the problem often becomes much more noticeable. Here’s why:
- Dilated pupils: In low-light conditions, your pupils get larger to let in more light. This increases the amount of distorted light entering the eye, exaggerating visual effects.
- High-contrast light sources: Against a dark background, headlights and streetlamps stand out more, making streaks and halos easier to notice.
- Glare sensitivity: Astigmatism often increases glare, especially when driving at night.
Symptoms of Astigmatism
People with astigmatism may describe nighttime lights as:
- Starbursts: Lights with multiple rays radiating outward
- Streaks or lines: Elongated beams extending from a light source
- Halos: Glowing rings or haze surrounding lights
But astigmatism isn’t only about how lights look. Depending on the degree, you might also notice:
- Fuzzy or blurry vision at both near and far distances
- Squinting to try to see more clearly
- Eye strain, especially after reading or computer work
- Headaches from prolonged visual effort
- Difficulty adjusting between light and dark environments
It’s worth noting that almost everyone has at least a small amount of astigmatism. In mild cases, symptoms may not be noticeable. But when it’s more significant, it can interfere with daily activities.
Types of Astigmatism
There are different types of astigmatism depending on where the irregular curve is located and how it affects vision.
- Corneal astigmatism: The cornea (the clear front surface of the eye) is unevenly curved. This is the most common type and the one most people mean when they say “astigmatism.”
- Lenticular astigmatism: The lens inside the eye has an irregular shape, causing light to bend unevenly.
Astigmatism can also be described based on how it interacts with nearsightedness or farsightedness:
- Myopic astigmatism: When astigmatism occurs alongside nearsightedness (myopia).
- Hyperopic astigmatism: When it occurs with farsightedness (hyperopia).
- Mixed astigmatism: When one meridian of the eye is nearsighted and the other is farsighted.
And finally, eye doctors often categorize astigmatism based on the direction of the curve (the “axis”):
- With the rule: The cornea is steeper vertically.
- Against the rule: The cornea is steeper horizontally.
- Oblique: The steepest curve is at an angle, not vertical or horizontal.
Living with Astigmatism
Astigmatism affects people differently depending on lifestyle. Some may only notice mild blur, while others struggle daily. Common challenges include:
- Driving at night, especially on busy Boise roads, where oncoming headlights feel blinding
- Using computers for long hours, leading to eye strain and headaches
- Kids in school, who may squint at the whiteboard or struggle with reading clarity
- Athletes, who might find fast-moving balls or bright stadium lights harder to track
Correcting astigmatism can make all of these situations more comfortable and safer.
How Astigmatism Is Diagnosed
The only way to know for sure if astigmatism is causing your nighttime vision problems is to have a comprehensive eye exam. During your exam, your optometrist will use a series of tests to measure how your eyes bend light.
We often hear patients say, “I thought it was normal for lights to look that way.” But after testing and prescribing the right lenses, many are surprised at how crisp and comfortable their night vision becomes.
Treatment Options for Astigmatism
Fortunately, astigmatism is highly treatable. Depending on your needs and lifestyle, options include:
- Eyeglasses: Glasses are the simplest and most common correction method. Lenses are shaped to bend light so it focuses evenly on the retina.
- Contact lenses: Soft toric lenses are specifically designed for astigmatism, and rigid gas permeable (RGP) lenses can also provide excellent clarity.
- Ortho-K (orthokeratology): Special lenses worn overnight gently reshape the cornea while you sleep, providing clear vision during the day without glasses or contacts.
- Laser surgery: Procedures like LASIK or PRK can permanently reshape the cornea for eligible patients.
Your optometrist will help you decide which option is best based on your eye health, lifestyle, and preferences.
Why It Matters
Astigmatism isn’t just about clearer vision. It’s about comfort and safety. Correcting this eye condition can:
- Make night driving safer by reducing glare and starbursts
- Reduce eye strain and headaches
- Improve performance at work and school
- Enhance quality of life by making everyday activities more comfortable
Here in Boise and the Treasure Valley, where long winter nights and snowy roads can already make driving a challenge, having sharp night vision is especially important.
When to See Your Eye Doctor
If you notice lights looking streaky, starry, or hazy, don’t ignore it. Even if you’ve had glasses or contacts before, your prescription may need updating. Vision changes gradually, and an annual eye exam helps ensure you’re always seeing your best.
At Emerald Point Eye Care, we check for astigmatism as part of every comprehensive exam and walk you through your options for correction.
Final Takeaway
Seeing starbursts or halos around lights at night is often a sign of astigmatism. With the right correction, you can reduce glare, sharpen your night vision, and feel more confident behind the wheel.
If you’ve been wondering why headlights look so streaky or why streetlights seem to glow, schedule an exam. Clear, comfortable vision is closer than you think.
