In the Shurangama Sutra, the Buddha reveals that what we take to be the real world may not be real at all, but rather distorted perceptions of reality arising from perceiving the world through our body and its senses – he called this the false perceptions arising from individual karma.
Using the analogy of a person with cataracts who sees the illusion of haloes around lights at night, the Buddha says that we have mistaken a thief for our own son. We have taken appearances to be reality in the same way that the haloes are not real, but can seem real to someone with cataracts.
However, once the cataracts are removed, no more haloes are seen. That which perceives the faulty film is not faulty.