After waking up in the morning, put on the glasses and weather forecasts and日程安排 appear on the lenses. When in a foreign country, a simple tap on the temple provides real-time translation of foreign signs. During meetings, the glasses record key information and automatically generate meeting minutes. This is not a scene from a sci-fi movie, but everyday functions of smart glasses.

According to the latest report released by International Data Corporation (IDC), global smart glasses shipments reached 14.773 million units in 2025, a year-on-year increase of 44.2%. The Chinese market grew 87.1% year-on-year, leading globally with shipments exceeding 2.46 million units. Smart glasses are rapidly transforming from "geek toys" into mass-market consumer products.

Three categories: each with unique strengths

"Currently, smart glasses on the market are mainly divided into three categories: visual enhancement type, 'audio+capture' type, and health monitoring type," said Tong Xinyu, Associate Professor at the College of Computer Science and Technology, Tianjin University, to a Tech Daily reporter.

Visual enhancement smart glasses use optical waveguide technology to overlay virtual information such as weather forecasts and navigation onto the real-world field of view. The working principle: a micro-display chip inside the glasses emits image light, which is transmitted via optical waveguide technology and projected from the lens onto the human retina, making the user feel as if the image is floating several meters away. For example, some binocular full-color smart glasses can achieve a 1080P projection effect, equivalent to a 120-inch virtual screen suspended before the user's eyes.

"Optical waveguide technology lays an 'optical track' inside the lens of visual enhancement smart glasses, allowing light to undergo total internal reflection and accurately project onto the user's retina, ensuring display clarity while avoiding the bulkiness of traditional prisms," Tong Xinyu explained.

"Audio+capture" smart glasses resemble ordinary sunglasses in appearance, with built-in dual cameras, microphone arrays, and speakers, supporting first-person perspective shooting, real-time translation, and voice assistant interaction.

Tong Xinyu introduced that these glasses feature two main technological breakthroughs: first, an ultra-compact camera sensor as small as a grain of rice, capable of recording 1080P high-definition video and capturing 3K resolution photos; second, AI noise reduction technology, which clearly records the user's voice even in noisy environments while filtering ambient noise. Additionally, these glasses support slow-motion and time-lapse photography, with capabilities comparable to a compact action camera.

Health monitoring smart glasses can monitor user fatigue levels, attention span, and even detect early signs of eye diseases.

"This is achieved primarily through two functions," Tong Xinyu explained. First is eye tracking and pupil analysis. An infrared micro-camera inside the glasses emits invisible infrared light toward the user's eyes, then captures pupil position, size, and change speed in real time. When a person is tired, pupil reaction slows down; when attention drifts, eye movements become erratic. By analyzing these subtle changes, the glasses can determine the user's state. The second function is retinal vessel imaging analysis. Some medical-grade smart glasses can capture retinal images to analyze whether vascular morphology is abnormal (such as bleeding points or twisted vessels), thus assisting in the diagnosis of diabetic retinopathy. The process is similar to using AI to identify objects in a photo taken with a phone, except here it identifies signs of disease.

Threats to information security and health

While providing convenience, smart glasses also harbor risks that cannot be ignored. Professor Xie Xin from the College of Computer Science and Technology, Tianjin University, believes these risks are like "scratches" on the lens — seemingly small but potentially affecting users' privacy, health, and even property security.

The most direct threat comes from privacy leakage. The camera of smart glasses can record everything in the user's field of vision 24/7, including other people's faces, important documents, and even private spaces at home. Although some smart glasses have an indicator light when recording, some manufacturers have removed this feature in pursuit of "stealth," further increasing the risk of covert recording.

A more insidious risk lies in data usage. Xie Xin explained that videos users shoot, voice commands they issue, and movement trajectories may be uploaded to the cloud for AI model training or precise ad profiling. For example, the terms of service for a certain smart glasses explicitly allow user data to be used for optimizing AI models, and most users, by clicking "agree," unknowingly surrender control over their personal data.

Eye health risks are also noteworthy. The display module of smart glasses is typically located 1 to 2 cm from the eyes. Prolonged viewing of virtual information can easily trigger "vergence-accommodation conflict" (VAC). "Simply put, VAC is a mismatch between the eye's focusing distance and the convergence distance of both eyes, leading to eye fatigue, headaches, and even nausea," Xie Xin explained.

In addition, payment and property security issues are hidden within seemingly convenient "touchless interaction." Smart glasses support voice payments and NFC near-field payments. However, if the microphone is hijacked by malware or the NFC module is not encrypted, payment passwords may be leaked. In 2025, a security team demonstrated live how to hijack smart glasses via a fake WiFi hotspot and successfully steal a user's bank account information.

These risks are not alarmist. As Wang Zhiqiu, a partner at Shenzhen Huadao Research Consulting Co., Ltd., stated: "Only by solving issues like privacy can smart glasses truly enter the daily lives of ordinary people."

Choosing the "second pair of eyes" wisely

Faced with a wide variety of smart glasses with diverse functions, how can consumers avoid pitfalls and choose products that truly meet their needs? Experts suggest making rational choices based on needs, privacy, and experience.

"Before buying smart glasses, consumers should clarify their core usage needs to avoid paying for features they won't use," Xie Xin added. If you only need them for lightweight scenarios like daily shooting or real-time translation, opt for glasses focused on audio and capture functions, paying attention to 1080P or higher resolution, microphone array noise reduction, and continuous battery life of no less than 4 hours.

"If you need immersive video watching or mobile office, visual enhancement smart glasses are a better choice," Xie Xin said. He recommends prioritizing products with a field of view no less than 50 degrees, brightness above 500 nits, and total weight under 50 grams for a more comfortable experience.

"Most health monitoring features are add-ons. Without clear medical needs, consumers don't need to pay extra for them," Xie Xin added.

"When selecting a product, be sure to focus on privacy security," Tong Xinyu believes. Consumers should prioritize products with on-device processing capabilities — meaning data can be computed locally without uploading to the cloud, reducing privacy risks at the source. Also, products should have a one-key off function for the camera and microphone and support high-strength data encryption like AES-256. For products with payment functions, confirm whether they have passed PCI DSS payment security certification to ensure fund and information security.

"Wearing comfort and display quality directly determine how often you'll use them," Xie Xin advised. He suggests consumers try them on offline whenever possible. While trying them, note whether the pressure on the temples is even, whether the nose pads support multi-level adjustment, and whether the lens light transmittance suits your daily environment.

If buying smart glasses with AR functions, consumers also need to test the edge sharpness of virtual images, visibility outdoors, and latency when the image follows head movements to avoid dizziness.

"In addition, software ecosystem and after-sales service are also critical," Tong Xinyu noted. Products equipped with mature AI large language models offer smoother voice interaction. Regarding after-sales, comprehensive warranty services provide greater peace of mind for long-term use.

According to IDC forecasts, global smart glasses shipments will exceed 40 million units by 2029, with China's market share continuing to rise. "While enjoying the convenience brought by technology, we also need to uphold the bottom line of privacy and security, finding a balance between technological innovation and ethical norms. Only then can smart glasses truly become the 'second pair of eyes' expanding our horizons," Xie Xin concluded.