Glasses featuring LCD lenses offer a convenient way to switch between correcting for near and distant vision.

Bifocal glasses have a history stretching back to the 18^th century, with designs that haven’t changed significantly over time. Typically, the lower section of the lens is shaped for nearby viewing, while the upper section is designed for distance, requiring wearers to shift their gaze frequently. A team led by Yi-Hsin Lin at National Yang Ming Chiao Tung University and Chuo Tung University in Taiwan has developed a pair of glasses that can toggle between two modes at the press of a button.

Rather than traditional glass lenses, these new lenses utilize a thin layer of liquid crystals controlled by an electric field, which alters the arrangement of the molecules to bend light in different ways depending on their function.

The concept of adjustable glasses using this principle, which produces the necessary electric field through thin electrodes embedded in the frame, is nearly 50 years old. However, advancements have been slow due to various technical obstacles. Lin and her colleagues have addressed some of these challenges, creating a wearable prototype.

The current iteration of these glasses offers a limited power range, boasting a functional viewing area of about 10 millimeters (3 to 4 times larger than traditional bifocals) and a switch time of approximately 5 seconds upon pressing the button on the frame. Nonetheless, Lin’s team has successfully identified the physical principles enabling these glasses to function effectively, and they are optimistic about future improvements in areas such as reducing switching times through electronic optimization. “Almost everyone will need prescription eyewear at some point, so the market potential is enormous,” claims team member Victor Reshetnyak from Taras Shevchenko National University in Kiev, Ukraine.

Viola Kanevsky, an optometrist in New York, notes that those most likely to benefit from these adaptive glasses are in technical fields where small objects may occupy significant visual focus or in professions requiring a broad perspective—such as architects evaluating long, straight lines or stockbrokers monitoring multiple large screens both near and far without needing to constantly adjust their heads.

However, these new prototypes are still far from being ready for clinical application due to the limited operational areas of the lenses, according to Mark Rosenfield from SUNY Optometry University in New York. The inclusion of electronic components also raises both the cost and complexity of manufacturing LCD glasses. Similarly, Joshua Silver from Oxford University highlighted that in 2004, he and his colleagues developed alternative self-adjustable eyeglass designs utilizing liquids.