Red Face Marks & Indentations from AR/VR Devices--A Dermatologist's Explanation
- Bryan Cho, MD PhD
- Aug 26, 2024
- 5 min read
The AR & VR market is expanding. Several next generation devices were introduced in the past year.
However an issue that may affect how quickly these devices are adopted are the red marks and indentations in the facial skin the some users have reported.
The most common skin irritation is a ring of redness that develops where the AR/VR device rests against the face. The cheeks and forehead seem to be the most common sites where this shows up.
This is a picture from a YouTube content creator who recently reviewed one of these AR/VR devices (I contacted the Gaming Guy and he was nice enough to give me permission to use these photos). He's pointing to a rectangular, stripe of red skin across his forehead. He described getting red marks on the forehead, temples and cheeks he calls "racoon eyes" that are sometimes tender after wearing his for device 30-40 minutes.
His experience isn't unique. Below are some links to his video and others who experienced something similar. In most cases the redness disappears pretty quickly...within minutes to an hour. Sometimes the skin might have temporary itchy or have a slight burning sensation.
Short-term redness is a normal skin response to something pressing firmly enough against the skin to close the tiny blood vessels which populate the skin surface. Closing these vessels, reduces blood flow and as result, the skin becomes low in oxygen. The lack of oxygen stimulates the closed blood vessels to produce chemicals called vasodilators. Vasodilators are signals our bodies generate to tell vessels to re-open as wide as possible and restore blood flow and oxygen levels as quickly as possible
However when an AR/VR device is physically pressing down against the skin, the vessels can't reopen regardless of the amount of vasodilator signals trying to counteract the pressure. The blocked vessels will continue to churn out vasodilator chemicals, so the longer blood flow is restricted, the higher the concentration of vasodilator chemicals that will encircle the closed vessels.
When the AR/VR device is removed eliminating the pressure against the skin, the vessels snap open and blood rushes back into the oxygen-deprived skin. To restore oxygen levels as fast as possible, the vasodilator chemicals increase the number and supersize the diameter of responding blood vessels. This creates a period of excess blood flow, called hyperemia, which rapidly restores the skin oxygenation and metabolic state back to normal.
Visually, when you look at the skin, excess blood flow (hyperemia) makes the skin look bright red. This is why skin that contacts the AR/VR device looks bright red for several minutes after the device is removed when worn at sufficiently high pressures. These are the areas of redness on the Gaming Guy's forehead, cheeks and temples shown in the pictures above.
How long the redness lasts is usually determined by how high the pressure applied to the skin is and the length of time before the pressure is removed. The higher the pressure and the longer the time the pressure was applied, then the longer the redness will last.
This whole sequence of Normal blood flow -> Pressure -> No blood flow -> Excess blood flow is called Reactive Hyperemia because the hyperemia occurs as a reaction to some external trigger. Reactive hyperemia is a normal physiological reaction that occurs many times throughout our day. For instance, on our back after reclining in a chair or under the bridge of our nose after wearing glasses.
This diagram from Dr Richard Klabunde, PhD, helps illustrate the changes in blood flow in response to periods of restricted blood flow (no flow). Notice the amount of blood flow after the pressure is removed (excess flow) is temporarily higher than the blood flow before the pressure was applied.
New imaging techniques allow us to directly visualize the process of reactive hyperemia. Here is an image of the skin using a technique called OCT (from Wang-Evers et al 2021), reproduce by creative commons license). The bottom, left side of the figure shows a snapshot of the blood vessels as if we were looking directly down into the skin. The red lines are the actual skin blood vessels that are visualized with the OCT scanner. When external pressure is applied to the skin, the vessels close (the red vessels in the OCT image disappear - middle figure). When the external pressure is removed, the vessels reopen within seconds and are larger in diameter and greater in density than before the pressure was applied (bottom, right side of the figure). The blue line measures the change in vessel density (# vessels in the field of view) before, during and after the pressure is applied to the skin.
There are other factors which can affect the duration of the facial redness and the what the skin feels like. Heat which accumulates between the AR/VR surfaces and the skin and friction from the device rubbing against the skin might make the skin turn more red or make the redness last longer.
Sometimes the high pressure with which these devices are worn, not only affects blood flow but also puts enough pressure on the skin to displace interstitial fluid causing indentations to develop. Indentations from facial masks worn on the skin under high pressures and for long periods of time was something medicals providers noticed during the Covid-19 pandemic. Here are some pictures from a publication by Coyer et al 2020 (reproduced below using a creative commons license) show some of the skin issues that arose. When indentations like these occurred, the medical providers more frequently developed discomfort or skin injuries. Indentations in the skin is a sign of tissue deformation which can lead to skin injury especially when a rigid device is held against the skin at high pressures.
The take home message from these more extreme outcomes is that if the redness lasts longer than a few hours (>24h) and the discomfort is greater than mild symptoms, then the pressure and/or the duration the AR/VR device is worn is likely greater than the user's skin can tolerate. Indentations in the skin should be taken as a clear warning sign that the pressure which which the device is being worn may cause greater discomfort or skin injury.
Reducing the pressure with which the device is worn against the skin and wearing the device for shorter periods may help relieve the symptoms and make your AR/VR device more comfortable to wear.
Most companies that make AR/VR devices have more than 1 option for headstraps. Third-party companies also make alternative headstrap designs. Some of these designs are made to offload facial pressure so the weight of the AR/VR device is carried by other parts of the head, like the scalp, instead of pressing against the face. Trying an alternative headstrap is a good option to reduce facial pressure from AR/VR devices but you may have to try several before you find one that works for you.
BOHLD consulting is a dermatology consultant for technology and medical device companies
We can help you understand the underlying cause of skin irritation related to an AR/VR or other wearable device
We evaluate device design to optimize skin comfort and safety
We evaluate material of skin interfaces or headstraps to optimize skin comfort and safety
Great to have medical explanations for why pressure marks happen on skin. AR/VR device companies can reduce marks on skin with better designs and materials.