Post: Maximizing Protection with Laser Safety Glasses: A Guide to Calculating Optical Density

Maximizing Protection with Laser Safety Glasses: A Guide to Calculating Optical Density

Laser safety glasses are essential when working with lasers, as they protect your eyes from harmful laser radiation. However, not all laser safety glasses are created equal. The amount of protection provided by a pair of laser safety glasses is determined by its optical density (OD) at specific wavelengths.

To calculate the optical density (OD) required for your laser safety glasses, you will need to know the following information: 

  • the wavelength of the laser 
  • the maximum power output of the laser


Once you have this information, you can use this following formula to calculate the required optical density: 

Optical Density = Log (Maximum Power Density Output/ Maximum Permissible Exposure).

*Where Maximum power density output and Maximum permissible exposure are both expressed in the same units of joules/cm2 or watts/cm2

*The Maximum Permissible Exposure (MPE) is determined by the American National Standards Institute (ANSI) and is based on the wavelength of the laser. You can find the MPE for your laser by referring to the ANSI Z136.1 (Table 5b ) standard.

Or, an easier method, is to use the Laser Institute of America’s free OD Calculator to determine the required OD. 

*Please note that if you have a pulsed laser, instead of continuous wave, you need to know the energy per pulse, pulse width, pulse repetition for the calculator

Disclaimer: This is for educational purposes only. For a definitive calculation of the OD required by your laser equipment, consult a Certified Laser Safety Officer or professionals at a laser safety glasses company.


In conclusion, calculating the optical density of your laser safety glasses is a crucial step in ensuring maximum protection when working with lasers. By following the steps and the formula outlined above, or using the LIA free OD calculator,  you can determine the required optical density for your specific laser application and select the appropriate laser safety glasses to keep your eyes safe.

If you need help in selecting the appropriate laser glasses or goggles for your eye safety requirements, the laser safety specialists at Phillips Safety are available to assist you. Our laser glasses are designed to meet or exceed the ANSI Z136.1 requirements, ensuring that you receive the highest level of protection possible. We offer free consultations and calculations for Optical Density, so you can make an informed decision about which laser safety glasses to choose.

If you still aren’t sure about the optical density for your laser safety glasses, it’s a good idea to give us a call at 1-866-575-1307 or talk to us through our chat or e-mail us at

Our laser experts will be able to tell you what you need for your application.