Refresh options created with WordPress Settings API?

I’m developing a theme-specific plugin to handle most of the theme’s functions. I have a few settings pages, and a couple of them create options by primary categories. For example, a settings page with an option to upload a banner image for each parent category to be used on that category’s archive page. The basic code is like this:

public static function option_fields() {
    $prefix = 'otw_category_banner_';
    $categories = get_categories( 'parent=0' );
    // Only need to initiate the array once per page-load
    if ( ! empty( self::$theme_options ) )
        return self::$theme_options;
    $fields = array();
    foreach ( $categories as $category ) {
        $fields[] = array(
            'name' => __( $category->name, 'cmb' ),
            'id'   => $prefix . $category->term_id,
            'type' => 'file',
            'allow' => array( 'url', 'attachment' ) // limit to just attachments with array( 'attachment' )
        );
    }
    self::$theme_options = array(
        'id'         => 'theme_options',
        'show_on'    => array( 'key' => 'options-page', 'value' => array( self::$key, ), ),
        'show_names' => true,
        'fields'     => $fields,
    );
    return self::$theme_options;
}

This code works fine initially, but after the initial options have been created it doesn’t seem to update when, for example, a new parent category is added. I’m a novice developer and first time poster so any help would be greatly appreciated.