If you notice that your child may be agitated and you aren't sure why. One thing you can try is changing the light source or dimming the lights to see if that helps to calm the child. Whenever possible, offer your child different lighting sources that they can choose from.
I notice early on that my son, much like me, gets agitated when forced to deal with bright artificial light over a long period of time. So I sought out different light sources for his room. He has a window where he is able to get natural light. There are also 3 lamps in his room. One clip-on desk lamp with a soft, dim, low wattage bulb (he can bend the neck in many directions, changing the lights effects), A regular desk lamp with appropriate bulb for doing school work and reading and a lava lamp. He prefers green or sometimes amber lava lamps. My son is able to pick an choose what lighting source he wishes to use.
This is another thing that may help to make the child's space more comfortable and allows him/her to make choices within their special space.