9.2 Safety Eyewear

9.2 Safety Eyewear

Industrial Safety Standards: ANSI Z87.1

In the United States, safety eyewear is not merely a product category but a highly regulated system of protection governed by the American National Standards Institute (ANSI) Z87.1 standard. This standard defines the design, testing, marking, and usage requirements for occupational and educational personal eye and face protection devices. Unlike dress (everyday) eyewear, safety eyewear is engineered to protect workers from specific industrial hazards, including flying projectiles, chemical splashes, dust, and optical radiation.

Opticians play a critical role in safety compliance. They must ensure that the lenses and frames dispensed match the safety level required by the wearer’s employer or work environment. Under ANSI Z87.1, safety eyewear is divided into two primary performance tiers: Basic Impact and High Impact. Both frames and lenses are tested and certified to these standards.

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Basic Impact vs. High Impact Standards

The distinction between Basic Impact and High Impact safety eyewear involves different test methods and lens thickness requirements.

Basic Impact Safety Eyewear (Z87)

Basic Impact eyewear is designed for environments with lower risks of high-velocity flying debris.

• Testing Protocol: Lenses are subjected to the Z87 Drop-Ball Test. A 1-inch (25.4 mm) steel ball is dropped from a height of 50 inches (127 cm) onto the front surface of the lens. The lens must not crack, chip, shatter, or dislodge from the safety frame. (Note that the Z87 drop-ball test uses a much larger and heavier ball than the standard FDA dress lens test).
• Thickness Requirements: To withstand this impact, basic safety lenses must have a minimum center thickness of 3.0 mm for all materials. The only exception is for prescription lenses with a plus power of +3.00 D or greater, which may have a reduced center thickness of 2.5 mm.
• Markings: Basic safety frames are marked with Z87 on the front and temples. Lenses are marked only with the manufacturer's logo or trademark.

High Impact Safety Eyewear (Z87+)

High Impact eyewear is designed for high-risk industrial environments (e.g., machining, grinding, woodworking).

• Testing Protocol: High-impact lenses and frames must undergo two rigorous tests:
  1. High-Velocity Impact Test: A 1/4-inch (6.35 mm) steel ball is shot at the lens at a speed of 150 feet per second (fps), which is approximately 102 miles per hour. The safety frame (without lenses, using plano test lenses) must withstand a 1/4-inch steel ball shot at 250 feet per second.
  2. High-Mass Impact Test: A pointed, 1-pound (454 g) steel projectile is dropped from a height of 50 inches (127 cm) through a tube onto the lens mounted in the frame. This test ensures the frame can retain the lens and resist heavy, blunt forces without collapsing.
• Thickness Requirements: Because high-impact materials are highly flexible and shatter-resistant, lenses made of polycarbonate or Trivex are permitted to have a minimum center thickness of 2.0 mm. However, if high-impact glass or basic plastic (CR-39) is used, the minimum thickness must remain 3.0 mm. Polycarbonate is the industry standard for safety due to its inherent impact resistance and built-in UV protection.
• Markings: High-impact safety frames are marked with Z87+ (or Z87-2+ for prescription frames). Lenses must be marked with the manufacturer's logo followed by a plus sign (+) (e.g., "XY+").

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The FDA Drop-Ball Test for Dress Eyewear

To understand the rigor of safety eyewear, opticians must contrast it with the Food and Drug Administration (FDA) impact resistance regulation for dress (everyday) eyewear under 21 CFR 801.410.

The FDA requires all dress spectacles and sunglasses sold to the public to be impact-resistant.

• Testing Protocol: The standard dress lens test utilizes a 5/8-inch (15.9 mm) steel ball weighing approximately 0.56 ounces (16 grams). The ball is dropped from a height of 50 inches (127 cm) onto the front surface of the lens. The lens must not fracture or crack.
• Exemptions: Specialty lenses that could be damaged by the test (such as laminated lenses, plastic lenses in some circumstances, or custom prescription designs) can be exempted, but they must still meet equivalent safety profiles. In modern practice, plastic dress lenses (CR-39, polycarbonate, Trivex) are rarely individually tested.
• Testing Frequency:
  • Glass Lenses: Glass is a brittle material. Therefore, the FDA mandates 100% individual testing. Every single glass dress lens must be individually drop-ball tested after undergoing chemical or thermal tempering.
  • Plastic Lenses (CR-39, Polycarbonate, Trivex): These materials are inherently more flexible. The FDA allows batch testing (statistical sampling of a manufactured lot) rather than testing every individual lens.

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Safety Markings and Compliance

ANSI Z87.1 requires permanent and legible markings on both the frame and the lenses to ensure compliance. If a frame or lens lacks these markings, it cannot be legally distributed or used as occupational safety eyewear.

Frame Markings

Safety frames must contain markings on the front (bridge or eyewire) and on both temples:

• Manufacturer's Mark: The logo or trademark of the manufacturer (e.g., "Uvex" or "3M").
• Z87: Indicates the frame meets the basic Z87 safety standards.
• Z87-2: Indicates the frame is certified for prescription (Rx) safety lenses (as opposed to plano safety glasses).
• "+" Symbol: Placed after the Z87 marking (e.g., Z87-2+), indicating the frame is certified for high-impact protection.
• Size Markings: Eye size (A-measurement), double bridge width (DBL), and temple length must be engraved.

Lens Markings

Safety lenses must contain markings in the upper-temporal corner, positioned so they do not interfere with the wearer's line of sight:

• Manufacturer's Logo: Identifies the lens manufacturer.
• "+" Symbol: Indicates the lens is high-impact rated.
• Specialty Codes:
  • W: Welding filter (followed by a shade number from 1.3 to 14).
  • U: Ultra-Violet (UV) filter (followed by a scale number from 2 to 6).
  • L: Visible light filter (followed by a scale number from 1.3 to 10).
  • R: Infrared (IR) filter (followed by a scale number from 1.2 to 10).
  • V: Variable tint (photochromic) lens.
  • S: Special purpose lens.

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Side Shields and Lateral Protection

A major safety hazard in industrial settings is debris flying from the side. Frontal protection alone is insufficient. Under ANSI Z87.1, safety eyewear must provide lateral (side) protection to be compliant.

Permanent vs. Removable Side Shields

• Permanent Side Shields: These are molded as part of the safety frame or permanently riveted to the temples. They cannot be removed without damaging the frame. Permanent shields are preferred in high-risk environments because they eliminate the risk of the worker removing them.
• Removable Side Shields: These can be slipped onto or clipped off the temples.
  • Critical Rule: Removable side shields must be specifically tested, certified, and marked for use with that exact frame model. An optician cannot legally place generic, unapproved slip-on side shields on a safety frame. The side shields must stay locked onto the frame and withstand the same high-velocity impact forces as the frame itself.