I found here that 涙 is a semasio-phonetic character (形声文字) while 泪 is a more visual version. Apart from that no big differences should be between this two ways of writing "namida". Anyway I would like to be sure of that.
Thank you very much!
Edit: I searched 泪 on google. Although the results are mostly in Chinese there are also results in Japanese. See for example here.