Mesopic lenses allow for testing with the CSV-1000, ESV-3000, and ESC-2000 at lower luminance levels, simulating nighttime driving conditions.

When the vision testing devices are set to a light level of 85 cd/m², the 2.0 ND lenses provide for a testing light level of approximately 0.85 cd/m².

*ND refers to Neutral Density. Neutral Density lenses reduce all visible light spectrum equally so that vision testing at lower luminance levels can be as highly accurate as testing at the higher luminance levels.