June 28, 2021 | Jerry Bergman

Eyes Have a Well-Designed Support System

 

The Eye Support System is Functional and Well-Designed:
Brow ridges, eyebrows, and eyelashes all serve important roles

 

by Jerry Bergman, PhD

All knowledgeable persons agree that the human eye is well-designed, but what about its surrounding structures? Examples of supportive structures include the brow ridges above the eyes, eyebrows, eyelashes, and the sometimes unsightly bags below the eye. The main purpose of the first three—brow ridges, eyebrows and eyelashes—is to protect the eyes, “whether it’s liquid, whether it’s solid, whether it’s dust, whether it’s bugs or insects.”[1] They are especially effective to protect the eyes from dust and sweat which can irritate. or even damage, the eye’s surface.[2]

Eyebrow hairs grow outward, toward the sides of the face, which directs moisture away from the eyes and toward the side of the head. When, in the hot summer sun, sweat starts flowing down your forehead, notice that the eyebrows are positioned along the brow bone to help channel sweat away from the eyes. As a result, sweat flows down the side of the face and not into the eye.

Eyebrows can also reduce the amount of light that gets into your eyes, especially reflected light. Lastly, any broad blow to the eye is protected by the brow ridges (Figure 1). This also helps deflect sweat to the side as do the eyebrows. An illustration of this protection from bright light achieved by holding one hand perpendicular to the forehead, the palm facing down, with the thumb extended.

Figure 1. Note the prominent brow ridges on the skull on the right (Wiki Commons). The smaller brow ridges on modern human skulls could be considered a functional loss, not an improvement.

Communication

Amazing FactsAnother function of the eyebrows is communication. They are especially effective communicating emotion, as expressed in the phrase “he raised his eyebrows after noting they were talking about him.”[3] One raised eyebrow is common to express skepticism or interest, two raised eyebrows expresses surprise.[4] The face has a total of 43 muscles, including the small muscles, many of which attach to the skin to move the forehead, eyebrows, lips, and cheeks. They “broadcast a wealth of information about our emotional state, level of interest and alertness,” said an article in The Smithsonian.[5]  At least seven visibly distinctive eyebrow emotions can be communicated by the eyebrows, including surprise, sadness, fear, and anger.[6] Another function of the eyebrows is sexual attraction. This is why many women color their eyebrows and eye lashes in an effort to enhance their attractiveness. Women who lose their hair and eyebrows due to cancer treatment often feel a great loss (Figure 2).

Figure 2. A woman who lost both her eyebrows and her head hair from cancer treatment.

In the process of face reconstruction for forensics work, eye brows are important in helping to identify the offender. The kits (now done by computer such as Identikit) includes an assortment of  eyebrows which, users have learned by experience, are a very important part of correct identification.[8]

Of note is that Charles Darwin included several pages in his book The Expression of the Emotions in Man and Animals showing the importance of eyebrows for communication.[7] He went into detail describing the specifics of eyebrow movement, which he stressed was an important means of conveying emotion. He also added several  illustrations to document their importance, as shown in Figure 3.

Beyond looks and emotions, eyebrows are also more generally important for facial recognition than eyes alone. In one widely reproduced study, scientists asked a group of people to identify the faces of fifty famous people, including U.S. presidents and well-known actresses.[9] The researchers manipulated the photos so that they would either have no eyes or no eyebrows. Of the pictures lacking eyes. subjects could still identify famous faces 60 percent of the time but, in contrast, when the faces lacked eyebrows, subjects could identify them only 46 percent of the time. The researchers concluded that

the absence of eyebrows in familiar faces leads to a very large and significant disruption in recognition performance. In fact, a significantly greater decrement in face recognition is observed in the absence of eyebrows than in the absence of eyes. These results may have important implications for our understanding of the mechanisms of face recognition in humans as well as for the development of artificial face-recognition systems.[10]

Figure 3. From Charles Darwin, 1872. The Expression of the Emotions in Man and Animals. London, UK: John Murray. The illustration is facing page 180 and shows the important role eye peripheral structures (e.g., brow ridges, eyebrows, eyelashes) play in conveying human emotion.

Genetic and Environmental Influences

It is well-established that the shape, color, and thickness of eyebrows are all inherited traits. Furthermore, a strong relationship exists between inheritance of specific genes and eyebrow appearance. Specifically, our separate genes affect eyebrow-hair texture, one gene dictates eyebrow shape, five genes regulate eyebrow hair color, and one gene determines if you develop a monobrow, meaning one single long eyebrow that runs above both eyes. Furthermore, years of waxing or tweezing eyebrows can permanently affect their shape, as can skin injuries near the eyebrows. In addition, some genetically-caused abnormalities exist, including madarosis, or eyebrow and or eyelash loss.

Eyelashes

Eyelashes are also necessary to protect the eyes, especially from dust and light. Wythe Eye Associates says, “Eyelashes are a first line of defense for your eyes, keeping airborne dirt, dust, lint and other debris from reaching the delicate eye tissues. With eyes open, eyelashes catch some airborne debris, but when closed, eyelashes form a nearly impenetrable barrier against foreign irritants.”[11]

Eyelashes serve another critical function in eye safety. The eyelash system is incredibly sensitive. If you touch the tip of one of your eyelashes, no matter how lightly, you will sense the finger immediately. Touching the eyelashes triggers the body’s blinking reflex, which impedes a foreign object from entering the eye. If a foreign object does enter the eye, it will most likely irritate, or possibly, in the case of sharp objects, could scratch, the eye cornea or conjunctiva. Scratches usually heal but can be very uncomfortable for a few days. Any foreign material near the eye, including cosmetics, also risks eye infection and allergic reactions. The high level of sensitivity of the blinking reflex is why it can be challenging to keep the eyes wide open while using eye drops, inserting a contact lens, or applying makeup.[12]

Evolutionary Implications

According to evolution, modern humans evolved from some hairy ape ancestor over millions of years. As they evolved, evolutionists claim, humans lost most of their body hair except on the head and above our eyes. In this view, eyebrows are merely a remnant of what was left after the rest of the hair was lost.[13] We are now naked apes except for our head hair and eyebrows, and for men, facial hair. This view undermines the functional benefits of eyebrows.

Some parts surrounding the eye are not so much designed as artifacts of poor health habits. As any sleep-deprived person with a mirror knows, dark circles under the eyes are usually prominent after a poor night’s sleep. The causes of the dark, purplish eye bags are both genetic and environmental, a result of rubbing eyes or getting too little sleep. Eye bags are more noticeable in people who have thin or pale skin. When tired or stressed, blood circulation in the eye area tends to slow, allowing blood to pool there. Capillaries eventually stretch and leak, leading to puffy, dark-eye circles.[14]

Summary

While not critical for survival, eyebrows and eyelashes are a central means of communication and attractiveness. This is especially important in human societies. They also serve important roles to protect our eyes. Without their protection, the risk of eye infections and surface damage, such as scratching the cornea, would be far greater. They are well-designed to serve these functions, and do so silently and effectively.

Editor Comment: Darwinism expects every trait to emerge because of selective pressure for survival. As Dr Bergman has shown, humans could survive fine without eyebrows and eyelashes, but would be the poorer for it. These are examples of traits designed for beauty, comfort and protection that are difficult to explain in Darwinian terms — not that Darwinists would be at a loss to come up with just-so stories to explain them anyway.

References

[1] Santora, Tara. 2021. Why do we have eyebrows and eyelashes? Do they serve a function beyond style? LiveScience.

[2] Landau, Terry. 1989. About Faces: The Evolution of the Human Face. New York, NY: Bantam Doubleday Dell Publishing Group, p. 103.

[3] Landau, 1989, p. 155.

[4] Liggett, John. 1974. The Human Face. New York, NY: Stein and Day.

[5] Adler, Jerry. 2015. Smile, Frown, Grimace and Grin — Your Facial Expression Is the Next Frontier in Big Data. Smithsonian Magazine, December, pp. 49-52, p. 48.

[6] Landau, 1989, p. 155.

[7] Darwin, Charles. 1896. The Expression of the Emotions in Man and Animals. New York, NY: D. Appleton & Company, pp. 179-180.

[8] Landau, 1989, p. 48.

[9] Sadr, Javid, et al., 2003. The role of eyebrows in face recognition. Perception 32(3):285-293, March 7.

[10] Sadr, et al., 2003.

[11] Wythe Eye Associates. 2020. “How Eyelashes and Eyebrows Protect Your Eyes,” Wythe Eye Associates, July 22.

[12] Wythe Eye Associates, 2020.

[13] Cohen, Jr., M. Michael. 2006. Perspectives on the Face. New York, NY: Oxford University Press.

[14] Geggel, Laura. 2016. Why do people get ‘bags’ under their eyes? LiveScience, November 23.


Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.

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