Many schools are introducing LED lighting.  Some LED lamps flicker and some do not.  There is little or no difference in price between LEDs that do and those that do not flicker.  Even lamps that are sold as "flicker-free" can flicker at high frequencies. This flicker may be invisible but can cause headaches and malaise - it doubles the average number of headaches in office workers1. Check for flicker by taking a video of the lighting using slo-mo on your smartphone. If flicker is visible, try and get the lighting changed, or keep the lamps off as much as possible.

1. Wilkins, A.J., Nimmo-Smith, I.M., Slater, A. and Bedocs, L. (1989) Fluorescent lighting, headaches and eye-strain. Lighting Research and Technology, 21(1), 11-18.