Howling:The retinal scanner for the Eye of Harmony in the TV Movie

Can anyone think of a good explanation as to why the Eye of Harmony inside the Doctor's TARDIS in the TV Movie had a retinal scanner keyed to only respond to a human eye pattern? Actually, why was there a scanner designed to open the Eye at all, if Time Lords aren't supposed to do that? 82.2.136.93talk to me 15:12, May 21, 2012 (UTC)