värikalvoa

Värikalvoa refers to the iris of the eye in Finnish. It is the colored part of the eye that surrounds the pupil and controls its size. The iris is a thin, circular structure made of muscle tissue and pigment. The pigment, melanin, determines the eye color. More melanin results in darker eye colors like brown or black, while less melanin leads to lighter colors like blue or green.

The primary function of the iris is to regulate the amount of light entering the eye. In bright light, the iris constricts the pupil, reducing the amount of light that reaches the retina. In dim light, the iris dilates the pupil, allowing more light to enter. This adjustment is an involuntary reflex, ensuring clear vision in varying light conditions. The iris also contains blood vessels that supply nutrients and oxygen to the eye.

The pattern and color of the iris are unique to each individual, similar to fingerprints. This uniqueness has led to its use in biometric identification systems. Diseases and conditions affecting the eye, such as iritis (inflammation of the iris) or heterochromia (a condition where a person has different colored irises or different colors within the same iris), can alter the appearance and function of the värikalvoa.