The idea of using iris patterns for personal identification was originally proposed in 1936 by ophthalmologist Frank Burch. Iris scans analyse the features in the coloured tissue surrounding the pupil which has more than 200 points that can be used for comparison, including rings, furrows and freckles. Because the iris is a protected internal organ whose random texture is stable throughout life, that one need not remember but can always present. The randomness of iris patterns has very high dimensionality; recognition decisions are made with confidence levels high enough to support rapid and reliable exhaustive searches through national-sized databases.