private function addIopReading(models\Element_OphCiExamination_IntraocularPressure $element, $eye_id, $value)
 {
     $reading = new models\OphCiExamination_IntraocularPressure_Value();
     $reading->element_id = $element->id;
     $reading->eye_id = $eye_id;
     $reading->reading_id = Yii::app()->db->createCommand('select id from ophciexamination_intraocularpressure_reading where value = ?')->queryScalar(array($value));
     $reading->save(false);
     return $reading;
 }