I didnt get any result even giving NVGoggles to civs, In OFP I end using the resistance civs present in editor updates, they were also as skilled as normal soldiers and were able to see at night much better than normal blind civs. I noted also that lightsources didnt solve the problem.
If desperate, you may try the following, put the day cloudly and in a time before 18:00. Create a resource inside titles covering all the screen with color [0,0,0,0.2] (a normal RscText), and try to make it so it does not expire. Then call it with CurRSC or TitleRSC, this will darken everything as if it were night. I know it is crazy, but it is also the last and only idea I can provide to make that civs to see in a fake-night.