Block visible only to the user who created it
You can use block visibility settings PHP code to check for specific users.

Please find the sample php code below.

&lt;?php
global $user;
$allowed = array('moderator','administrator'); // Allowed Roles
$allowed_uids = array(1, 5, 10); // 1, 5, 10 are user id's which you want to allow
$valid=FALSE;
foreach($user-&gt;roles as $role){
  if(in_array($role, $allowed) &amp;&amp; in_array($user-&gt;uid, $allowed_uids)) {       
    $valid=TRUE;
  }
}
return $valid;
?&gt;


See the screen show below where you need to write above code.