diff --git a/reference_option_limit.module b/reference_option_limit.module
index 17ba53e..6b1659f 100644
--- a/reference_option_limit.module
+++ b/reference_option_limit.module
@@ -136,6 +136,16 @@ function reference_option_limit_form_field_ui_field_edit_form_alter(&$form, &$fo
     '#default_value' => !empty($form['#instance']['options_limit_empty_behaviour']),
     '#parents' => array('instance', 'options_limit_empty_behaviour'),
   );
+
+  if ($form['#field']['type'] == 'entityreference') {
+    $form['instance']['options_limit_fieldset']['options_optomize_entityreferences'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Optimize entityreferences'),
+      '#description' => t('Prevent entityreference from loading all possible entities. May not work for all configurations; use with care.'),
+      '#default_value' => !empty($form['#instance']['options_optomize_entityreferences']),
+      '#parents' => array('instance', 'options_optomize_entityreferences'),
+    );
+  }
 }
 
 /**
@@ -508,6 +518,54 @@ function reference_option_limit_entity_query_alter($query) {
   }
 }
 
+
+/**
+ * Implements hook_query_TAG_alter().
+ */
+function reference_option_limit_query_entityreference_alter($query) {
+  $instance = $query->alterMetaData['entityreference_selection_handler']->instance;
+  $current_query_conditions = $query->alterMetaData['entity_field_query']->entityConditions;
+  if (!empty($instance['options_limit']) && !empty($instance['options_limit_fields']) && !empty($instance['options_optomize_entityreferences']) && empty($current_query_conditions['entity_id'])) {
+    $field = $query->alterMetaData['entityreference_selection_handler']->field;
+    $entity = $query->alterMetaData['entityreference_selection_handler']->entity;
+    $empty = !empty($field['options_limit_empty_behaviour']);
+    $field_name = $field['field_name'];
+
+    foreach (array_filter($instance['options_limit_fields']) as $field_name_matching) {
+      // @TODO Actually change the query to return the correct results here.
+      // The query has been converted to a simple select query now so can't
+      // add field fieldCondition.
+      if (_reference_option_limit_get_entityreference_values($field_name_matching, $entity, $_POST) || !empty($instance['options_limit_empty_behaviour'])) {
+        $query->condition('1', '0', '=');
+      }
+    }
+  }
+}
+
+/**
+ * Helper function to abstract the values of an entity reference field.
+ */
+function _reference_option_limit_get_entityreference_values($field_name, $entity, $check_values = array()) {
+  $values = array();
+  if (isset($check_values[$field_name])) {
+    $process = $check_values[$field_name];
+  }
+  elseif (isset($entity->$field_name)) {
+    $process = $entity->$field_name;
+  }
+  if (isset($process) && is_array($process)) {
+    if (!empty($process[LANGUAGE_NONE])) {
+      foreach ($process[LANGUAGE_NONE] as $items) {
+        if (!empty($items['target_id'])) {
+          $values[] = $items['target_id'];
+        }
+      }
+    }
+  }
+  return $values;
+}
+
+
 /**
  * Helper to get the names of fields have instances set to limited options.
  *