Ans.

The human retina is a thin tissue composed of neuralcells that is located in the posterior portion of the eye.

The retina is a light-sensitive layer in the back of the eye that contains highly evolved cells called rods and cones. It’s divided into the central (macula) and the peripheral retina. The macula has the highest concentration of photo-receptors (cones) and provides the sharpest vision. The peripheral retina is used for peripheral vision, which is critical for many activities, like driving and playing sports.

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. Capillaries absorb more of the infrared light than surrounding tissues, and the difference in how much light is reflected is measured and assigned numbers. These numbers are turned into a computer code, which is compared to codes stored in a computer.