diff --git a/pupil_src/shared_modules/fixation_detector.py b/pupil_src/shared_modules/fixation_detector.py
index c0c4fa8504..d0e768423f 100644
--- a/pupil_src/shared_modules/fixation_detector.py
+++ b/pupil_src/shared_modules/fixation_detector.py
@@ -564,11 +564,16 @@ def recent_events(self, events):
                 new_fixation['id'] = self.id_counter
                 self.id_counter += 1
 
+            self.replace_basedata_with_references(new_fixation)
             events['fixations'].append(new_fixation)
             self.recent_fixation = new_fixation
         else:
             self.recent_fixation = None
 
+    def replace_basedata_with_references(self, fixation):
+        fixation['base_data'] = [(gaze['topic'], gaze['timestamp'])
+                                  for gaze in fixation['base_data']]
+
     def gl_display(self):
         if self.recent_fixation:
             fs = self.g_pool.capture.frame_size  # frame height