I read an example that said this sentence was personal: Его ослепила молния and this one impersonal: Его ослепило молнией
To me they both mean "The lightning blinded him." I don't really understand how to tell the difference between a personal and impersonal sentence. Is it something like "he was blinded by the lightning" in the instrumental case as opposed to "the lightening blinded him" in nominative? When writing my own sentences what is the easiest way to know whether it is a personal or impersonal construction?