Iris Recognition vs. Retina Scanning — What are the Differences?

Noman Ahmed
Biometric Blog
Published in
2 min readFeb 26, 2019

In biometrics, iris and retinal scanning are known as “ocular-based” identification technologies, meaning they rely on unique physiological characteristics of the eye to identify an individual. Even though they both share part of the eye for identification purposes, these biometric modalities are quite different in how they work. Let’s take a closer look at both and then explain the similarities and differences in detail:

Retinal Scanning: The human retina is a thin tissue composed of neural cells that are located in the posterior portion of the eye. Because of the complex structure of the capillaries that supply the retina with blood, each person’s retina is unique. The network of blood vessels in the retina is so complex that even identical twins do not share a similar pattern. Although retinal patterns may be altered in cases of diabetes, glaucoma or retinal degenerative disorders, the retina typically remains unchanged from birth until death.

A biometric identifier known as a retinal scan is used to map the unique patterns of a person’s retina. The blood vessels within the retina absorb light more readily than the surrounding tissue and are easily identified with appropriate lighting. A retinal scan is performed by casting an unperceived beam of low-energy infrared light into a person’s eye as they look through the scanner’s eyepiece. This beam of light traces a standardized path on the retina. Because retinal blood vessels are more absorbent of this light than the rest of the eye, the amount of reflection varies during the scan. The pattern of variations is converted to computer code and stored in a database. Retinal scanning also has medical applications. Communicable illnesses such as AIDS, syphilis, malaria, chicken pox well as hereditary diseases like leukemia, lymphoma, and sickle cell anemia impact the eyes. Pregnancy also affects the eyes. Likewise, indications of chronic health conditions such as congestive heart failure, atherosclerosis, and cholesterol issues first appear in the eyes. Click to continue reading

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