New smart contact lenses could help fight glaucoma

Most individuals with early-stage glaucoma are unaware they have the condition, despite early intervention being crucial to mitigate vision loss. Detecting minor increases in eye pressure is essential for diagnosing glaucoma; however, continuous monitoring is complex, particularly given the varying temperatures the eyes endure. Researchers have recently developed a prototype ‘smart’ contact lens that accurately measures eye pressure irrespective of temperature changes, as detailed in the ACS Applied Materials & Interfaces journal.

Approximately three million people in the U.S. suffer from glaucoma, as stated by the Centres for Disease Control and Prevention. This group of diseases harms the optic nerve, leading to vision loss. Traditionally, doctors have used the discomforting ‘air puff tests’ to measure eye pressure momentarily during exams. A slight pressure increase, caused by fluid accumulation around the cornea, could indicate glaucoma. To enhance continuous and less intrusive pressure monitoring, researchers have explored alternatives like contact lenses that communicate data to receptor glasses. Nonetheless, temperature fluctuations, such as moving into colder environments, could disrupt the lens measurements. To address this, Dengbao Xiao and colleagues aimed to create a contact lens capable of consistently and wirelessly transmitting accurate eye pressure data across various temperatures.

The team engineered two miniature spiral circuits, each displaying unique natural vibration patterns altered by minute pressure changes or shifts in the eye's diameter. These circuits were encapsulated within layers of polydimethylsiloxane, a standard contact lens material. The vibrations from the circuits were wirelessly read via a coil connected to a computer, proving resilient against eye movement simulations, moisture exposure, and daily wear.

During lab tests on three pig eye specimens, with controlled ocular pressures and temperatures, the lenses monitored and wirelessly communicated pressure data across a temperature range from 50 to 122 degrees Fahrenheit. While single-circuit readings deviated significantly, combining data from both circuits minimised errors to 7% from actual values, effectively eliminating temperature-related discrepancies. Researchers believe this dual-circuit "smart" lens could significantly advance early detection and monitoring of glaucoma across diverse temperature conditions.

Find the original published article, here.