Are Auto-Darkening Welding Helmets Safe?

You should be very conscious about your health as a welder. A welding helmet is the most important safety tool to keep your eyes, skin, and lung safe. When it comes to protecting your eyes from the dangers of welding, the first thing to consider is whether the auto-darkening lens on your welding helmet actually works.

The main benefit of an auto-darkening lens is you don’t have to take your helmet off to line up welds and inspect your work.

Most critically, an auto-darkening lens helps prevent permanent damage to your vision.

Are Auto-Darkening Welding Helmets Safe?


Without eye protection while welding, the excessively bright light may damage your cornea, causing temporary or permanent blindness.

Auto-darkening helmets are the best choice in most cases because they instantaneously darken the lens to protect your eyes when arc light is detected.

Arc Light and Light Sensors

The light from a welding arc throws off intense ultraviolet radiation (UVR). This includes ultraviolet A (400–315 nm), ultraviolet B (315–280 nm) and ultraviolet C (280–100 nm). All of these UV rays can severely damage your eyes if left unprotected. Long-wavelength UVA radiation can also penetrate the cornea and be absorbed through the lens, potentially leading to eye cancer.

The intensity of welding arc light is very high. A MIG welder can generate roughly 5 watts per square meter (W/m2) of light. This is far higher than anything your eyes will be exposed to under normal conditions (even the sun). Such high intensity means that eye damage can be rapid.

Auto-darkening welding helmets come with multiple sensors in front to detect high-luminance welding arcs. As long as the lens battery is charged, the lens will automatically darken and block the majority of light.

Auto-Darkening Failure

There are two potential failure points with auto-darkening welding helmets that can leave your eyes dangerously exposed:

  1. Battery failure, reducing the ability to detect intense arc light
  2. Malfunction of the auto-darkening response, allowing excess light to reach the eyes

Battery Failure

Most auto-darkening welding helmets come with either standard batteries (usually AA) or an externally chargeable lithium battery.

As the battery wears down, the lens will become less responsive to your welding arc. By the time you notice this, it is usually too late, and you may already have gotten too much light in your eyes.

Because of this risk, it’s essential to keep fresh and well-charged batteries in your helmet.

Auto-Darkening Malfunction

Welding lenses that dynamically change shades are operated by software and sensors that trigger electrical pulses in the lens. As more electrical energy is applied to the lens material, it darkens by reorienting molecules in the glass.

In poor-quality welding helmets, the auto-darkening process can work inefficiently. This increases the response time and prevents the helmet from fully shading your eyes from the intense light of the arc.

The lens or sensors can malfunction entirely, as well. In this case the lens won’t darken at all (or will only darken sporadically), and your eyes will absorb all of the UV radiation from the weld arc. This is extremely dangerous.

Unfortunately, malfunctions can be hard to detect unless there are telltale “flickers” or other odd behavior. They are also not controllable by you like keeping the batteries charged.

If you detect a malfunction, stop using the helmet and take it to a certified support center for lens replacement.

What Happens To Your Eyes When You Weld Without an Auto-Darkening Helmet?

“Arc Eye”

If you fail to wear a welding helmet, or wear normal sunglasses, or your auto-darkening lense malfunctions, then you will likely get “arc eye” (aka “welder’s eye” or “arc flash”).

Arc eye is a term for the symptoms that occur when the membranes of the eye are damaged by excess high-intensity light.

The level of arc eye you get will depend on the intensity and duration of your welding, the distance from the welding arc, the light angle (i.e. staring straight at the weld or watching from the corner of your eye).

These are the general symptoms of arc eye:

  • Intense eye pain
  • Constantly tearing in the impacted eye
  • Red membranes surrounding the eye
  • Feeling like there is dirt or sand in the eye
  • Light sensitivity (photophobia)
  • Inability of the eyes to adjust to light conditions
  • Twitching
  • Headaches
  • Loss of vision, particularly night vision

Arc eye is an indicator of short-term damage and usually clears up within a day or two. Repeatedly getting arc eye can cause long term damage, however.

Temporary Blindness

Viewing the intense light of a welding arc from a short distance can cause temporary blindness. The light hitting the eye is so bright that the iris doesn’t have time to close. This allows intense light to reach the retina, overloading the light receptors.

If you allow your eyes to be directly exposed to high-luminescent welding arc light for an extended time, this can lead to temporary blindness lasting days or more.

Long Term Effects

UV radiation heats up your eye lenses, which can lead to cataracts.

As discussed above, long wavelength UVA radiation can impact the eyes and surrounding tissues. Studies have shown that extended exposure to UVA radiation can lead to cancer.

How Do Auto-Darkening Welding Helmets Work?

Auto-darkening helmets work in an interesting process that combines special glass with multiple layers and sensors. Here are the components required for auto-darkening welding lenses to work:

  • Arc and light sensors: The helmet has arc and light sensors at the front of the helmet, above the viewing port. These sensors detect the arc light when you start the weld and send a signal to darken the glass.
  • Viewing glass: There are several layers of glass filters, such as UV/IR filter, polarization filters, and several LC cells. Depending on the intensity of the light, these layers of glass will be triggered to darken or lighten.
  • Controls: Your welding helmet will have one or more knobs for controlling the shading, shading speed and angle of the viewing glass.
  • Powering the sensors: Auto-darkenig welding helmets come with different power sources such as AA batteries, lithium ion batteries or solar powered batteries. They are rechargeable or changeable.

Multiple Lens Shades

Auto-darkening welding helmets have up to 13 shading gradients, depending on the intensity of the arc.

You can adjust the shades with a knob inside or on either side of your helmet, depending where the light controls are. Usually, the shading will start at level 3 if you’re welding outside in the sun. Indoors the shades will usually start at 0 or 1.

As you move to a darker place or closer to the weld, the lens will transition to a darker shade very quickly. The peak darkness should block the vast majority of arc light, but still allow you to see the weld puddle and work shape in front of the weld.

Auto-Darkening Delay and Viewing Angle

You can adjust your helmet’s delay timing to control how fast the lens protects your eyes. This controls how long it takes to darken the viewing glass from it’s initial clear state.

You can also adjust the viewing angle so you don’t get any eye strain while looking at the piece in a normal position.

If you mis-adjust these settings, your eyes can be exposed to more UV radiation than you want. You should err on the side of caution and keep the auto-darkening speed set to fast. This way it will react quickly right when the arc starts and give you the maximum amount of eye protection.

Highly Rated Auto-Darkening Welding Helmets

YESWELDER True Color Solar Powered Auto Darkening Welding Helmet, Wide Shade 4/9-13 for TIG MIG ARC Weld Hood Helmet

Monster&Master Large Viewing Screen Auto Darkening Welding Helmet, 2 Arc Sensor Wide Shade

TOOLIOM Welding Helmet, True Color Auto Darkening 1/1/1/2 Large Viewing 3.94″x 3.27″ Welder Mask Hood

Auto-Darkening Helmet Care and Maintenance

Auto-darkening helmets are great at their job, but you have to take care of them to maintain a good service life.

Here are some maintenance tips:

  • Keep the battery charged — this will help avoid auto-darkening delays or failures.
  • Store the helmet in a clean spot — you shouldn’t store your welding helmet where dust, oil or chemicals can build up on the lens
  • Protect the lens — Don’t throw your welding helmet around, drive with it rolling around the bed of your truck, or throw it in a box with your tools. When you clean the helmet, use a microfiber cloth to sweep the glass area. Don’t use any chemicals or rough shop cloth to wipe the lens.

Frequently Asked Questions

Here are the most frequently asked questions about auto-darkening helmets that you must know about:

Can auto-darkening welding helmets damage your eyes?

Auto-darkening helmets don’t damage your eyes. As long as the battery has enough charge to power up the sensors and darken the lenses automatically, then these helmets are vision safe.

Keep in mind that the helmet should be properly adjusted, maintained and serviced to ensure the auto-darkening lens functions correctly. A malfunctioning or mis-adjusted lens can lead to eye damage.

How long do auto-darkening helmets last?

You can use an auto-darkening helmet for about 7 years with a replaceable or fixed battery. They generally lose functionality after that. The glass lens, mechanism and batteries should be changed.

Why is an auto-darkening welding helmet necessary?

Welding involves a lot of potential risks, including fire, electrocution, burns, ultraviolet radiation, toxic chemical exposure, vision damage and inhalation of fumes or gases. It’s impossible to deny the fact that you need proper head and eye protection for the job.

Auto-darkening welding helmets deliver two benefits for welders:

  • They protect your eyes from intense arc light damage (“arc eye”, temporary blindness, cataracts, cancer)
  • They contribute to higher weld quality and appearance by allowing the welder to see the work before starting the arc, watch the weld puddle and features in front of the puddle while welding, and see the resulting weld after finishing. The welder can do this without flipping an eye shield down or taking the helmet on and off. Welding becomes a lot more efficient and comfortable as a result.

Bottom Line

Auto-darkening welding helmets make your job faster, easier and higher quality. They protect you from severe eye damage and other harmful effects inherent in the welding process. Auto-darkening welding helmets are definitely safe and should be used by most welders.

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Nick Klamecki, Author
About Nick Klamecki, Author

Nick Klamecki is a certified Fire and Workplace Safety expert with 15 years experience in product research and testing. He has a degree from U.C. Davis, is an active outdoorsman and spent years ensuring the safety of special needs children. Nick researches and tests workplace, industrial and safety products and provides advice on their safe use. Learn more about Nick here or connect with him on LinkedIn | Medium