I believe the answer is EYE.
In order to find this out, we need to identify the body part that had the exact sequence of letters if we read it from left-to-rights and right-to-left.
The only body part that fulfil this criteria is : eye
The left-to-right spelling of EYE:
E - Y - E
The right-to-left spelling of EYE is also:
E - Y - E