Researchers from Northumbria University in the UK and Boğaziçi University in Turkey have developed contact lenses with embedded sensors that can measure the pressure inside the eye. These sensors send the information to an ophthalmologist for evaluation, with the hope that early diagnosis of glaucoma, a condition that can lead to irreversible vision loss, can be achieved.
Glaucoma occurs when the optic nerve, which connects the eye to the brain, is damaged due to increased intraocular pressure (IOP). This pressure is usually caused by a build-up of fluid in the front part of the eye. Unfortunately, glaucoma often develops slowly over time, causing irreparable harm before any vision loss is noticed. By the time glaucoma is detected during routine eye tests, it may already be too late.
However, this new collaboration between researchers has resulted in the development of contact lenses that can detect fluctuations in IOP. The lenses are made of a disposable soft material called polydimethylsiloxane (PDMS) and contain an electrically passive sensor. The data collected by these sensors is wirelessly transmitted to a wearable electronic readout system, which then processes the information. The processed data is finally given to an ophthalmologist for evaluation.
One of the advantages of using these contact lenses, known as GlakoLens, is that they allow for easier and more accurate IOP measurements over a longer period of time compared to conventional eye exams. According to Hamdi Torun, the corresponding author of the study, monitoring IOP continuously or at regular intervals throughout the day provides valuable insights into the health of patients’ eyes. Traditional methods of measuring IOP involve visiting a clinic for a single measurement, which can be misleading due to natural variations in IOP. If a variation is detected, further investigation is required, often involving hospitalization for repeated measurements using a technique called Goldmann applanation tonometry (GAT).
The GlakoLens contact lenses offer a less invasive alternative to these traditional methods. Once placed in the eye, patients can go about their day as usual while their IOP measurements are recorded. After a 24-hour period of testing, the data is sent to a doctor for analysis.
The researchers conducted a trial of their contact lenses on six healthy volunteers. These participants were asked to drink water and lie flat to intentionally increase their IOP. The contact lenses worn in the left eye collected data, while IOP measurements were taken in the right eye without the lens for comparison. The findings showed that the contact lens sensors responded to the effects of increased IOP due to water loading, and the measurements from the right eye were consistent with those taken by the device.
Further experiments using larger groups of healthy individuals will be conducted to assess the accuracy and reliability of the sensors. The researchers also plan to improve the comfort and non-invasiveness of the contact lenses in future iterations.
It’s worth noting that these are not the first glaucoma-detecting contact lenses to be developed. In February 2023, researchers from South Korea’s Pohang University of Science and Technology tested contact lenses that monitored glaucoma and released medication to reduce IOP when necessary. However, their lenses were only tested on rabbits. In May, a California-based startup trialed miLens, a ring placed in the eye that physically measured IOP on glaucoma patients. The readings provided by miLens were found to be just 2 mmHg different from GAT readings.
The researchers behind GlakoLens emphasize that their contact lenses offer greater comfort compared to previous designs. Previous lenses used an electrically active silicon chip, resulting in a thicker and less flexible lens that could restrict vision. In addition to diagnosing glaucoma, the researchers believe their lenses could be used to detect other health conditions by measuring molecules such as glucose and lactic acid present in the eye.
The study detailing the development of GlakoLens was published in the journal Contact Lens and Anterior Eye. The lenses are expected to be commercially available through the spin-off company GlakoLens.
Source: Northumbria University