You walk out of a bright restaurant into a dark parking lot and suddenly can't see anything for what feels like forever. Or driving at night has started feeling genuinely stressful — headlights bleed into halos, street signs appear at the last second, and you're squinting way more than you used to.
It's easy to chalk this up to "just getting older." Sometimes that's part of it. But worsening night vision almost always has a specific, identifiable cause behind it — and in many cases, it's fixable.
Here's what's actually going on.
How Your Eyes See in the Dark
Before getting into causes, it helps to know the basic mechanics.
Your retina has two types of photoreceptor cells: cones and rods. Cones handle color and fine detail in bright light. Rods are responsible for low-light vision. They contain a photopigment called rhodopsin, which bleaches when exposed to bright light and needs time to regenerate — that's why it takes a few minutes for your eyes to "adjust" when you step into a dark room.
When anything disrupts the rods, rhodopsin production, or the optical pathway from your lens to your retina, night vision takes a hit. That disruption can come from several directions.
Common Causes of Worsening Night Vision
Uncorrected or Outdated Prescription (Myopia / Night Myopia)
Blurry distance vision — nearsightedness (myopia) — can worsen in dim lighting, when the eye already struggles to focus. If your prescription is even slightly off, you might see fine during the day when there's ample light and contrast. But at night, the drop in ambient light strips away that cushion and the blur becomes obvious.
There's also a specific phenomenon called night myopia (nocturnal myopia). It affects both corrected and uncorrected eyes, with studies showing an average 13–20% loss of visual acuity. It causes drivers to feel like they have less control, making the driving experience more uncomfortable and more dangerous. Uncorrected hyperopia and astigmatism can also blur night vision.
If you haven't had your prescription checked in a year or more, an outdated script is one of the first things to rule out.
Cataracts
Cataracts generally develop as part of the natural aging process, as the proteins that make up the eye's lens begin to crystallize and harden. Decreased night vision and increased difficulty driving at night is typically the first sign of a developing cataract.
Cataracts scatter incoming light rather than letting it pass cleanly to the retina. This shows up as glare, halos around lights, and washed-out vision in low-light conditions — often before daytime vision is noticeably affected. It's one of the most common causes of night vision decline, especially from your 50s onward.
Vitamin A Deficiency
Vitamin A is essential for producing rhodopsin, the pigment your rod cells need to function in low light. An insufficient amount of vitamin A in the body affects rhodopsin production — and night blindness is usually one of the first signs of a deficiency.
Vitamin A deficiency is relatively rare in the US and Canada but worth knowing about, particularly if you have malabsorption conditions, have had weight loss surgery, or follow a highly restricted diet. Dietary changes can often reverse symptoms. Good sources include leafy greens, eggs, oranges, cantaloupe, and sweet potatoes.
Glaucoma
Glaucoma reduces peripheral vision and can make it harder to see at night. It occurs when fluid builds up in the eye and damages the optic nerve. Peripheral vision loss is one of glaucoma's earliest signs, and since peripheral vision is heavily rod-dependent, low-light environments make this deficit much more apparent.
Worth noting: some glaucoma medications, such as brimonidine, that constrict the pupil can also impair night vision as a side effect. However, many doctors actually prescribe pupil-constricting eyedrops to reduce glare while driving at night.
Retinitis Pigmentosa and Genetic Conditions
Retinitis pigmentosa (RP) is a group of inherited disorders that cause progressive breakdown of rod cells. Degeneration and death of rods in the early stages leads to loss of peripheral and nighttime vision, often described as tunnel vision. Night blindness is typically among the first symptoms, often appearing in adolescence or early adulthood.
For genetic conditions like RP, there is currently no cure. The focus is on managing symptoms and limiting the progression of effects where possible.
Age-Related Changes
Even without a diagnosable condition, your eyes change structurally over time. As you age, the pupils tend to become smaller and less responsive to light changes. The lens of the eye also gradually yellows and becomes less transparent, reducing the amount of light reaching the retina. Most people notice these changes beginning around age 40–50.
These changes are gradual and cumulative, which is part of why night driving tends to feel harder with each passing decade even when your annual eye exam comes back "fine."
Certain Medications
Some drugs — such as glaucoma treatments, retinoids, or phenothiazines — can reduce pupil size or affect the retina's ability to adapt to darkness, making nighttime vision more difficult. If your night vision has gotten worse around the same time you started a new medication, it's worth mentioning to your prescribing doctor.
What You Can Actually Do About It
- Get your prescription updated.
This is the lowest-hanging fruit. Even a small refractive error that's manageable in bright light can become noticeable at night when contrast is lower. An updated prescription for glasses or contact lenses is usually the first thing to check.
- Add an anti-reflective (AR) coating to your lenses.
An anti-reflective coating on eyeglasses can help reduce glare, especially while driving at night. This is especially useful if headlights and streetlights produce halos or streaks in your vision.
- Look at your diet.
If vitamin A deficiency is on the table, increasing intake of foods like sweet potatoes, carrots, leafy greens, and eggs is a reasonable first step before looking at supplements. Talk to your doctor before supplementing, since vitamin A is fat-soluble and excess amounts accumulate.
- Address the underlying condition.
Night blindness caused by cataracts can be treated by removing the cataracts themselves. Cataract surgery involves replacing your eye's cloudy lens with a new and clear artificial lens — and your night vision will improve significantly if cataracts were the underlying cause. Glaucoma management, blood sugar control for diabetic patients, and other condition-specific treatments can all meaningfully improve night vision.
- Practical short-term adjustments.
Keep your windshield and headlights clean, adjust your mirrors to reduce headlight glare, and avoid staring directly at oncoming headlights. These won't fix the underlying cause but make night driving more manageable in the interim.
When to See an Eye Doctor
Don't wait if you notice:
- Sudden worsening of night vision (as opposed to gradual decline)
- Tunnel vision or significant loss of peripheral vision
- Halos, starbursts, or severe glare around lights
- Night vision difficulties paired with eye pain or redness
- Any rapid change in vision at any time of day
Night blindness isn't something you can self-diagnose or self-treat. A comprehensive eye exam gives your optometrist or ophthalmologist the tools to identify whether you're dealing with a straightforward prescription issue, an early cataract, early glaucoma, or something that needs specialist referral.
The earlier you catch most of these conditions, the more treatment options are on the table.
Frequently Asked Questions
Keep Your Prescription Current
Clear night vision starts with the right lenses. Whether you need prescription contacts for everyday wear or want to explore our FDA-cleared colored contacts for dark or light eyes, EyeCandys makes it easy to find lenses that work for your lifestyle — and your eyes.
