Rule Definition
An empty catch block defeats the purpose of exceptions. When an exception occurs, nothing happens and the program fails for an unknown reason. The application can be in an unknown state that will affect subsequent processing. Since the reason for the issue (the type of the exception and potential embedded message) are not known, it will require more time to fix the issue.

Remediation
The exception must be handled properly according to its type.

Violation Code Sample

class CAST{
    public function close() {
        if (true) {
            echo 'test';
        }
    }
}

Fixed Code Sample

<?php

/**
  * Doc comment
  * @param int    $counter  counter
  * @throws RuntimeException if counter is 1
  */
function afunction($counter) {
   if (1 === $counter) {
      throw new RuntimeException("Bad parameter!");
   }
}

class ThrowsTagUse {
   /**
     * Doc comment
     * @param int    $counter  counter
     * @throws RuntimeException if counter is 1     
     */
   public function __construct() {
      if (1 === $counter) {
         throw new RuntimeException("Bad parameter!");
      }
   }

   /**
     * Doc comment
     * @param int    $counter  counter
     * @throws RuntimeException if counter is 1
     */
   public function aMethod() {
      if (1 === $counter) {
         throw new RuntimeException("Bad parameter!");
      }
   }
   
}

?>

Code Sniffer - http://pear.php.net/package/PHP_CodeSniffer/docs/1.5.2/PHP_CodeSniffer/Squiz_Sniffs_Commenting_FunctionCommentThrowTagSniff.html