protected function generateStructuredVisionTable()
{
$field_of_vision_data = $this->generateFieldOfVision();
$low_vision_data = $this->generateLowVisionStatus();
// mismatch in row count between the two lists.
$low_vision_data[] = array('', '');
// empty header row
$data = array(array('', '', '', ''));
for ($k = 0, $k_max = count($field_of_vision_data); $k < $k_max; $k++) {
$data[$k + 1] = array_merge($field_of_vision_data[$k], $low_vision_data[$k]);
}
return $data;
}