What is the minimum thickness for safety lenses: A Comprehensive Guide


In environments where eye hazards are prevalent, the correct choice of safety glasses is essential. The effectiveness of safety eyewear significantly depends on the thickness of the lenses. This article will explore the minimum thickness requirements for safety lenses, focusing on high-index plastic, glass, polycarbonate, Trivex, and standard CR-39 plastic. Grasping these standards is critical to ensuring that your safety glasses comply with ANSI Z87.1 or ANSI Z87+ industry standards and afford the highest level of eye protection.

The Significance of Lens Thickness

Lens thickness is critical for safety lenses’ ability to resist impacts, pressure, and various environmental dangers. Safety lenses are designed to maximize protection without compromising visual acuity. The minimum thickness for each type of material is established based on its impact resistance and robustness, guaranteeing that the lens can provide sufficient defense against anticipated hazards.

Minimum Thickness Requirements by Material

Polycarbonate lenses are celebrated for their exceptional impact resistance and lightweight properties, making them the optimal choice for safety lenses. The minimum thickness required for polycarbonate safety lenses is 2.0 mm, making them ideal for safety glasses, sports eyewear, and children’s glasses due to their excellent protection against high-speed impacts.

Glass lenses provide unmatched scratch resistance and optical clarity but are heavier and more susceptible to shattering upon impact than their counterparts. To be used safely in hazardous environments, glass safety lenses must maintain a minimum thickness of 3.0 mm to meet ANSI Z87.1 basic impact protection. This requirement addresses the material’s weight and impact resistance limitations, making glass lenses less common in safety eyewear applications.

High-index plastic lenses are thinner and lighter than traditional lens materials, offering an aesthetically pleasing option for prescription safety glasses. However, to meet the ANSI Z87.1 standard for safety glasses, high-index plastic lenses must have a minimum thickness of 3.0 mm. This adjustment ensures that even with their slim profile, high-index lenses are sufficiently robust to provide adequate impact resistance for safety purposes.


Trivex lenses offer a superior combination of lightweight, high impact resistance, and optical clarity, with a minimum thickness of 2.0 mm. These lenses present a significant advantage for individuals seeking safety eyewear that is protective, light, and comfortable for prolonged use.

Standard Plastic Lenses (CR-39)

Standard plastic lenses, or CR-39, are favored for prescription lenses but exhibit lower impact resistance than polycarbonate or Trivex. To ensure safety, CR-39 lenses must have a minimum thickness of 3.0 mm to meet ANSI Z87.1. While they offer excellent optical quality, their thicker and less impact-resistant nature makes them less ideal for high-risk situations.


Selecting the appropriate material for your safety lenses is crucial to maintaining optimal vision and ensuring eye protection in hazardous settings. While polycarbonate and Trivex lenses remain preferred for most safety applications, high-index plastics have been adapted to meet ANSI Z87.1 standards with a minimum thickness of 3.0 mm. Whether choosing high-index plastics, glass, or standard plastic lenses, it’s essential to consider the risks and opt for a lens material that provides adequate protection without sacrificing visual quality or comfort. Investing in the proper safety eyewear is crucial in safeguarding your vision health and safety.


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