Contributors to Under-Eye Bags
Bags sometimes form under the eyes with age, but actually the passage of time is not the primary factor in under-eye sagging. Sometimes we blame lack of sleep for under-eye baggage. Tiredness though, while it does make a difference, is not the real culprit either. It's mostly genetics and the environment that work together to form those unsightly pouches.
The Genetic Factor
Heredity is what determines how much fat and skin you have around your eyes compared to the rest of your face. Some people genetically have flat contours around the eye area that simply will not ever bulge or sag. Other people may inherit a tendency to have fat deposits that protrude, either above or below the eye. Little can be done about heredity, but some people with natural under-eye bags notice that the bags increase or decrease with fluctuations in body weight. Also, bags that are present in youth are bound to become more pronounced when skin thins and loses its resiliency over time.
The Sun Does More Damage than Time
The passing years seem to accentuate eye bags, but really it's the hours spent in the sun that cause under-eye skin to thin and lose its resiliency. This is because ultraviolet rays change the way that skin cells regenerate, causing each successive generation of skin cells to be less able to form collagen. Collagen is the protein that makes skin firm and elastic. So less collagen means more drooping and sagging. This is true of all skin on the body, but areas where the skin is already naturally thinner--like under the eyes--have less natural protection from sun damage.
No matter the initial cause, the appearance of under-eye bags can be dramatically affected by everyday environmental factors. For instance, bags will be most noticeable when you first wake. This is because fluids accumulate in the facial tissues when you spend several hours lying down. Also, anything that causes you to retain excess water, such as eating a lot of salt, may cause facial tissues to swell.
Allergies may cause swelling of the mucous membranes and sinus tissues including the area around the eyes. Irritation to the skin from soaps, perfumes or from rubbing the eyes can cause skin edema. Certain medications may cause swelling, and some medical conditions, like hyperthyroidism, can cause the eyes to protrude. All these things will make existing bags more pronounced.
Lack of Sleep Plays a Role, Too
Fatigue is probably the factor most often blamed for under-eye bags. In the short term, fatigue does not actually cause any changes to the skin or fat under the eye, but it does cause facial muscles to be more lax. Less muscle tension means that the skin will not be supported, and will droop more than when you are fully rested. Sustained levels of fatigue will affect your skin's ability to regenerate and heal. Your skin may become less resilient and those under-eye bags could hang around for a while.