2024-12-15
Welding Without Proper Eye Protection Is Not an Option
This is not one of those articles where the advice is "it depends on your preferences." If you weld, you need proper eye protection. Full stop. A welding arc produces intense ultraviolet and infrared radiation that can cause photokeratitis (essentially a sunburn on your cornea, also called "arc eye" or "welder's flash") in seconds of unprotected exposure. Long-term, chronic UV exposure from welding is associated with cataracts and other serious eye conditions.
If you also need prescription lenses to see clearly, you have two basic options: prescription safety glasses worn under your welding helmet, or prescription inserts that mount inside the helmet. Both work, but understanding the safety ratings and how they apply to your specific situation will save you money, frustration, and potentially your eyesight.
Understanding the Safety Standards
CSA Z94.3 (Canadian Standard)
This is the Canadian standard for eye and face protection. In Alberta and most other provinces, occupational health and safety regulations require that workplace eye protection meets CSA Z94.3. If your employer provides safety glasses or requires you to buy your own, they need to meet this standard. CSA-certified safety glasses are marked with "CSA Z94.3" on the frame and sometimes on the lenses.
ANSI Z87.1 (American Standard)
The ANSI standard is widely recognized in Canada as well, and many safety frames carry both CSA and ANSI certifications. The ANSI Z87.1 mark on a lens tells you it has passed high-velocity and high-mass impact tests. If you see "Z87+" on the lens, that means it passed the high-velocity impact test (a quarter-inch steel ball fired at 150 feet per second). The "+" matters: plain "Z87" means basic impact only.
What the Rating Actually Means
A safety-rated lens must withstand a 1-inch steel ball dropped from 50 inches (basic impact) without cracking, chipping, or dislodging from the frame. The high-velocity "+" rating ups this to a quarter-inch ball at 150 fps. For welding, where you are exposed to sparks, spatter, and flying slag, the high-velocity rating is what you want.
Regular prescription glasses, even with polycarbonate lenses, are not safety rated. The lenses might survive an impact, but the frames are not designed to hold the lenses in place under force. A regular frame can deform and launch a lens fragment into your eye, which is arguably worse than no glasses at all.
Shade Numbers: What They Mean
Welding filter lenses are rated by shade number, which indicates how much visible light they block. The higher the shade number, the darker the filter. The shade you need depends on the welding process and amperage:
| Process | Amperage Range | Minimum Shade |
|---|---|---|
| Oxy-acetylene cutting | n/a | 3-5 |
| SMAW (stick) | Under 60A | 7 |
| SMAW (stick) | 60-160A | 8-10 |
| SMAW (stick) | 160-250A | 10-12 |
| GMAW (MIG) | Under 60A | 7 |
| GMAW (MIG) | 60-160A | 10-11 |
| GMAW (MIG) | 160-500A | 10-14 |
| GTAW (TIG) | Under 50A | 8-10 |
| GTAW (TIG) | 50-150A | 8-12 |
| Plasma arc cutting | Under 300A | 8-9 |
Your prescription safety glasses worn under a welding helmet do not need to be welding-shade rated. The helmet filter handles the shade protection. Your under-helmet glasses just need to be clear, safety-rated, and protect against sparks and debris when you flip the helmet up between welds.
Option 1: Prescription Safety Glasses Under the Helmet
This is the most common approach and usually the most practical. You wear a pair of prescription safety glasses (rated CSA Z94.3 or ANSI Z87.1+) as your everyday shop glasses, and your welding helmet goes over top when you are welding.
Advantages:
- You can see clearly all the time, not just when the helmet is down
- They protect your eyes from grinding, cutting, and other shop hazards when you are not welding
- They work with any welding helmet
- Easier to replace one pair if your prescription changes
Disadvantages:
- Fit can be tight under some helmets, especially bulky frames
- Fogging when the helmet traps warm air around your face
- The helmet headgear can press on the temple arms
For under-helmet use, choose compact frames with thin temple arms. Wraparound styles can be hard to fit under a helmet. Anti-fog coatings are almost mandatory here because the enclosed space under a welding helmet is a fog factory.
Option 2: Prescription Inserts for the Helmet
Some welding helmets accept prescription lens inserts that mount inside the helmet, between the auto-darkening filter and your face. These are custom-made with your prescription and clip into a bracket inside the helmet.
Advantages:
- No glasses pressing against your face or competing with the headgear
- Better helmet seal and fit
- More comfortable for extended welding sessions
Disadvantages:
- You cannot see clearly when the helmet is up or off — you need separate safety glasses for grinding and other work
- Not all helmets support inserts
- If your prescription changes, you need new inserts
- More expensive in total since you still need a separate pair of shop safety glasses
Auto-Darkening Helmets and Prescription Lenses
Modern auto-darkening helmets are a major improvement over the old flip-down passive filters. They allow you to see your workpiece clearly in the light state (usually shade 3-4) and darken to the set welding shade in milliseconds when the arc strikes. This means you can position your work, tack, and weld without flipping the helmet up and down.
For glasses wearers, auto-darkening helmets are especially helpful because you do not need to repeatedly lift the helmet (and deal with the glasses-shifting-under-headgear problem) between welds. Just keep the helmet in position, and it handles the shade transitions for you.
Make sure your helmet's viewing area is large enough that your prescription lenses do not create a "picture frame" effect where you can only see through a portion of the filter. Large-view auto-darkening helmets (4 x 3 inches or larger) work best with prescription eyewear underneath.
Lens Material Matters
For welding safety glasses, polycarbonate is the standard lens material. It is inherently impact-resistant, lighter than glass, and blocks 99.9% of UV radiation even without additional coatings. Trivex is another excellent option that provides slightly sharper optics than polycarbonate with similar impact resistance, but it costs more.
Do not use glass lenses in a welding environment. They can shatter on impact from spatter or debris, and they are heavier, which matters on a long shift.
What to Bring When You Order
When you come in for prescription safety glasses for welding, bring your welding helmet if you can. We can check the fit of the frames inside the helmet and make sure the temple arms do not interfere with the headgear. Tell us what welding processes you do, whether you also grind or cut, and how many hours a day you wear them. If your employer has specific safety requirements (certain CSA or ANSI ratings), bring that information too. We will make sure your glasses meet the standard and actually work for how you weld.