Wearable technology is all the rage these days. From people sporting Google (NASDAQ:GOOG) (NASDAQ:GOOGL) Glass on their morning run to fitness bands that track their activity level, wearables are quickly growing into a multibillion-dollar market. Here are three ways wearable technology is already changing the way we live and interact with the world around us.

All eyes on medical devices
Wearable technology creates an opportunity to integrate the digital into the physical, and companies such as Google are demonstrating how this can improve our health in the process. Google kicked off 2014 by introducing a revolutionary contact lens that monitors a wearer's glucose levels. Using a tiny wireless chip and glucose sensor, Google's prototype can measure glucose levels in people with diabetes, thus creating a more efficient way of monitoring the disease.

In a blog post, Google said, "At Google[x], we wondered if miniaturized electronics -- think: chips and sensors so small they look like bits of glitter, and an antenna thinner than a human hair -- might be a way to crack the mystery of tear glucose and measure it with greater accuracy." The search giant is now working on a prototype that integrates miniature LED lights that would light up to warn the wearer that his or her glucose levels have "passed above or below certain thresholds."

While it will take some time for this technology to be ready for the market, it promises to forever change the way people and doctors deal with diabetes.

Palm scanners promise to transform the payment space
A smart technology called Biyo (formerly known as PulseWallet) lets consumers make payments by scanning the unique vein patterns in their hands. Once your palm is paired with your credit card, you simply hold your hand over one of these Biyo payment terminals and the credit card on file will be charged. The system is now available for businesses and costs $1,999 per terminal.

Source: Biyo Wallet.

At this point, the technology is mostly used outside of the U.S. in markets such as Brazil and Italy, according to The Verge. Nevertheless, with a half-second response time, this palm recognition software could revolutionize the payments industry by letting consumers pay in stores with just the wave of their hand. What's more, the company's creators say this technology is more secure than other forms of electronic payment because it's unique to each specific customer.

While it could take some time for people to become comfortable sharing their unique vein pattern with merchants, this could be a welcome remedy for the various forms of credit card fraud that exist today -- ahem, Target. One thing is certain, wearable tech, along with smartphone devices, will play an increasingly important roll in shaping the payments industry.

Making mind control a reality
Wearable tech is also shaping the future through brain-powered headgear. This is no longer the stuff of science fiction. Today, companies such as Emotiv and InteraXon are creating mind-bending devices that actually let you execute basic smartphone commands using your mind. A person wearing InteraXon's Muse headband, for example, could adjust their phone's volume or brightness using only his or her thoughts.

Systems like these work with head-mounted electroencephalogram, or EEG, sensors that measure your brain's electrical activity. The Emotiv Insight headpiece is being used in a variety of ways today, including patient rehabilitation by allowing patients to control an electric wheelchair or type without physically using their hands. These may seem like simple tasks for the average person, but for someone with limited mobility, these types of brain-computer interfaces can be life changing.

InterAxon's Muse device. Source: InterAxon.

Imagine the possibilities for this technology in the emerging Internet of Things realm -- think thought-activated home lighting. As these companies and others continue to unlock the full potential of this brain-sensor tech, we should see more breakthrough applications in everyday life.

Together, these are three key ways that wearable devices are changing the way we interact with the world around us. Looking ahead, wearables offer an exciting opportunity for consumers and investors.