The iris in our eyes

What is the iris?

The iris is the colored part of the eye that surrounds the pupil. The iris plays an important role in regulating light entering the eye and also determines eye color.

Eye color and the iris

De kleur van de iris, en dus de oogkleur, wordt bepaald door de hoeveelheid en het type pigment genaamd melanine. Melanin is the same pigment responsible for the color of the skin and hair. The main factors that influence eye color are:

1. Genetics
   Eye color is largely determined by genetic factors. Specifieke genen reguleren de productie en distributie van melanine in de iris.
2. Melanin concentration
   • Brown eyes: These contain a high concentration of melanin, which causes them to absorb most light waves and appear dark. Brown is the most common eye color. This
     This is because brown is genetically the dominant eye color.
   • Blue eyes: These contain less melanin and the structure of the iris scatters light, making it appear blue.
   • Green eyes: These have a medium amount of melanin, and the way light is scattered by the iris structure creates a green color.
   • Hazel eyes: These have a mix of colors and melanin concentrations that give a combination of brown, green and sometimes gold tones.
3. Light scattering
   The phenomenon of light being scattered by the fibers in the iris also contributes to the perceived eye color. This is especially significant with blue and green
   eyes.

Unique and rare eye colors

1. Grey eyes
   Very rare and caused by an even more complex combination of melanin concentration and light scattering.
2. Red eyes
   Occurs in people with albinism. This is due to the lack of pigment, which makes the iris transparent and the blood vessels in the eyes visible. As a result, this color appears in red.
3. Heterochromia
   A condition in which a person has two different colored eyes, or one eye with multiple colors.

Changes in eye color

Eye color can change in some cases due to age, illness or injury. In babies, the eyes contain little pigment in the first few months. As a result, the eyes are often blue in principle and the color changes as they grow older and produce more melanin. After six months the eye color is usually permanent. Eye Color After Blepharoplasty The brightness of the iris may subjectively appear to change after blepharoplasty, but this is usually an optical effect caused by changes in how light enters the eye. The procedure itself has no direct influence on the structure or color of the iris.

Window reflex

The fenestration reflex refers to a phenomenon in which light entering through the eyes is reflected by the surface of the eye, specifically the iris. This reflex may become more apparent after eyelid surgery for a few reasons:

1. Less shade
   Excess skin or drooping eyelids can create shadows that darken the eye, the iris. After removing this excess skin, there is less shadow and light can be reflected better, making the iris appear brighter.
2. Better Eye Contours
   Tighter eyelids provide better definition of the eye contours, which can influence light and reflection. This can make the iris appear brighter due to the improvement in eye contour.
3. Healthier Appearance
   After a successful eyelid correction, the eyes can generally look healthier and younger. This can give the impression that the iris is brighter, when in fact this is due to the improved overall appearance of the eye area.