Retinal scanning is the process of analyzing the unique patterns of a person’s retina for identity verification and authentication purposes. This technology was first available on the commercial market in 1981, but references to retinal scanning have been used in science fiction entertainment dating back as far as 1966 with Star Trek and Batman. Retinal scans are sometimes used to gain entry to high-security offices or access to computers or other electronic equipment.
Because the retina is not based on genetic information, retinal scans are as unique to each individual as fingerprints. When an accurate scan is taken, there are very few instances of false positives and even fewer instances of false negatives. However, an accurate scan is often difficult to obtain, so it often requires multiple attempts. This can be uncomfortable for the person whose retina is being scanned and can make it difficult to process multiple scans in a short amount of time. For this reason, retinal scanning is less frequently deployed than other methods of biometric identity verification.
A retinal scan uses a beam of infrared light that passes through the pupil to map the unique network of retinal blood vessels located at the back of the eyeball. The whole scan takes about 30 seconds. The pattern is then digitized using computer software and stored in a database so it can be recalled when a match is needed. When someone’s retina needs to be verified, a new scan is taken that is compared to the digitized image in the database.
Retinal scanning is sometimes conflated with iris recognition, another biometric technology that uses the colored part of the eye surrounding the pupil. However, retinal scanning uses beams of light to map blood vessels at the back of the eyeball, whereas iris recognition uses high definition cameras to capture an image of the eyeball surface. Iris recognition is usually faster and more accurate than retinal scanning and is also a much less invasive technique.
Retinal scanning is not harmful for eye health, although the need to keep one’s eye open and close to the scanning device for the required length of time can cause discomfort. In fact, the same technique is used by optometrists to check for glaucoma, macular degeneration, diabetic retinopathy, and other retinal health issues during dilated eye exams.