Lighting
Lighting plays an important role in how we see.
Red light
Red light is made of low frequencies of light and is refractively the near form of light. Therefore, red light might cause significant eye strain, but is the clearest light for myopic users.
Green light
Green light is made of middle frequencies of light. In colorblindness it may merge with red light (in some cases with blue light instead). Duochrome tests are sometimes performed to detect undercorrection or overcorrection by determining whether red light or green light is clearer.
Blue light
Blue light is made of high frequencies of light and is refractively the distant form of light. In full correction, is therefore the most relaxing form of light. This paragraph will be the most comfortable one to read with full correction. However, full correction to blue light leaves red and green light overcorrected.
Lighting during eye exams
- "That said, according to international ophthalmic standards (aka ISO 8596:2017), the luminance or brightness should be between 80-320 lux uniformly across the exam room during a proper visual acuity exam. This includes the eye chart and the room itself.
- As a point of comparison, 350-375 lux is equivalent to a 25-watt incandescent bulb at full brightness. So yeah, that is pretty darn dim."[1]