Retina vs. Iris Recognition: Similarities and Differences

Besides fingerprint and facial recognition, eye scanning is one of the most highly mentioned biometric modalities these days. As the security market rapidly increases, it is expected that eye recognition solution would grow fast at a CAGR of 23.40% between 2015 and 2020, reported by MarketsandMarkets. The recognition of retina and iris are known as eye-based identification which means they rely on unique physiological attributes of the eye to identify an individual. However, there are certain differences in the way they work.

retina vs iris recognition

Retina is the thin layer that is on the inner back of the eye. It is a complex structure of blood vessels that even identical twins do not have a similar texture, thus, it is unique for each person. However, the retina patterns can be changed in case of diabetes, glaucoma or degenerative disorders of the retina. A retinal scan is performed by sending out an unobserved low-energy infrared light beam into a person’s eye as they look into the scanning device. This beam of light traces the systematized path of the retina. As the blood vessels of the retina are more light absorbent than the rest of the eye, the amount of reflected light varies during scanning. The result received is the pattern of those variations.

Quite different from retina, iris is flat, ring-shaped tissue behind the cornea of the eye. The iris contains muscles that adjust the size of the pupil and regulate the amount of light that enters one’s eye. The color of the iris defines the eye color. For some people, retina scanning is often confused with iris recognition. Iris recognition is an automated method of biometric identification that uses video camera technology with near infrared illumination (NIR) to capture images of the detail-rich structures of the iris. The images are turned into digital templates and stored in a database. These templates provide a mathematical representation of the iris, or in other word, it represents a person identity.

Although retina scanning and iris recognition have some aspects in common such as: low false acceptances and false rejections rate (1 in millions), high reliability (even identical twins do not share the same pattern of iris or retina), quick verification, etc.; there are apparently typical differences between these two modalities.

  • Stability: while the accuracy of retina scan can be affected by diseases; the iris texture remains extremely stable because it is internal and protected, yet externally visible part of the eye.
  • Invasion: while iris pattern can be captured with NIR from a distance which is totally safe for human eye; retina scan requires a very close encounter with the scanning device by using a beam of light deep inside the eye which is considered to be invasive.

For those reasons, iris identification technology is more widely accepted and deployed in different industries. Up to date, roughly 1 billion of people around the world have been enrolled in iris recognition systems for security and convenience purposes such as: national ID, border control, finance and banking, etc. Many governments already used the technology as a means of highly secured identity management and it’s expected to soon enter the massive commercial sectors such as: automotive, mobile and internet of things.