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 the lenses will lead to early diagnosis of glaucoma, a condition that can cause irreversible vision loss if left untreated.
Glaucoma occurs when the optic nerve, which connects the eye to the brain, is damaged by increased intraocular pressure (IOP). This pressure is usually caused by a build-up of fluid in the front part of the eye. Unfortunately, glaucoma is often referred to as the “silent thief of sight” because it develops slowly over time, causing irreparable harm before any vision loss occurs. By the time glaucoma is detected during routine eye tests, the damage may already be done.
However, this new collaboration between researchers has led to 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. Data collected by the sensor is wirelessly transmitted to a wearable electronic readout system, which then processes the information. The processed data is then 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 compared to conventional eye exams. Traditional methods often involve a single measurement at a clinic, which can be misleading due to natural variations in IOP. If a variation is detected, further investigation is required, which typically involves hospitalization for repeated measurements using a technique called Goldmann applanation tonometry (GAT). This method requires numbing drops and touching the cornea with a small cone to measure pressure. In contrast, GlakoLens allows patients to go about their day as normal while their IOP measurements are recorded and sent to a doctor for analysis once the 24-hour testing period is complete.
The researchers conducted a trial of the contact lenses on six healthy volunteers. These participants were asked to drink water and lie flat to intentionally increase their IOP. The contact lens sensors responded to the effects of water loading, and the measurements from the lens-less right eye were in agreement with those taken by the device.
Further experiments using larger groups of healthy individuals will be conducted to investigate the accuracy and reliability of the sensors. The researchers also plan to optimize the comfort and non-invasiveness of the contact lenses in future iterations.
While these contact lenses are not the first to detect glaucoma, they offer advantages over previous designs. Other lenses have used electrically active silicon chips, resulting in thicker, less comfortable lenses that restrict vision. In contrast, GlakoLens uses an electrically passive sensor and a soft contact lens, ensuring greater comfort for wearers.
In addition to diagnosing glaucoma, the researchers believe that their lenses could be used to detect other health conditions by measuring glucose, lactic acid, and other molecules present in the eye.
The study was published in the journal Contact Lens and Anterior Eye, and the lenses are expected to be commercially available through the spin-off company GlakoLens.
Source: Northumbria University