proper try .. catch

should i controlling slight throwing errors:

if (isset($this->dbfields[$var])) {
    relapse $this->dbfields[$var];
} else {
    pitch new fieldnotfoundexception($var);
}

or style:

try {
    relapse $this->dbfields[$var];
} locate (exception $e) {
    pitch new fieldnotfoundexception($var);
}

...or something else altogether?

quick reason code: $this->dbfields an array. isset() checks non-static set, case, presumably array component exists.