Self-powered System-On-contact-Lens for Intraocular Pressure Measurement in Patients with Glaucoma



Researchers want to develop a contact lens with a small sensor that can monitor eye pressure around the clock and release precise doses of medicine to patients with glaucoma.

A contact lens with a built-in pressure sensor and microchip can be important in the treatment of glaucoma patients in the future. The idea is that the lens is placed on the eye the same way as an ordinary contact lens, and it constantly registers changes in the fluid pressure that plays an important role in the development of the disease.

Untreated glaucoma can cause changes in the optic nerve and ultimately lead to blindness, but appropriate medical treatment with eye drops can prevent an increase in fluid pressure and the progression of the disease.

Round-the-clock monitoring of eye pressure
Glaucoma patients currently have their eye pressure (Intraocular pressure-IOP) measured by an ophthalmologist or at a hospital by means of a special instrument. The problem with this method is that it can only be performed periodically, for instance only during clinical hours, which does not provide enough valuable data. Therefore, the researchers will design an intelligent lens that can monitor the eye pressure at intervals of just a few seconds twenty-four hours a day.

“We know that the ocular pressure in patients with glaucoma can vary from one moment to the next, and with considerable fluctuations in the course of a day. Using an intelligent lens, we can therefore make it much easier to monitor the disease and provide more accurate medical treatment,” says Associate Professor Farshad Moradi.

The researchers will initially develop the electronics required for the lens so that it can store information about pressure and send a message to a computer or smartphone about when to take eye drops and in what dosage.

In the long run, they also expect to provide the lens with a polymer layer containing nanomedicine, which can be regularly and very precisely released in the eye based on pressure monitoring.

Power from the Sun and eye movements
Dr Moradi is an expert in developing microchips, and he collaborates with both ophthalmologists and materials researchers in the project. In its first state he will develop the computer technology so the contact lens is supplied with sufficient data capacity and processing power. The idea is to make the lens capable of working entirely without battery power and processing all information on chip.

For this purpose, the researchers are already working on different power-generating technologies. A flexible solar cell, for example, can drive the electronics during daylight hours, and a special piezoelectric material will create elecwtrical energy at night via mechanical forces from rapid eye movements (REM) during sleep.

“We’ll be experimenting with different energy-harvesting methods to find the right mix regarding what can be done without compromising the comfort of the lens user. Our aim is to create so much processing power that the lens only needs to be changed ocassionally,” says Dr Moradi.

The researchers expect to have proof of concept and an early prototype of an intelligent contact lens in the course of three to four years.

Next step is cancer and diabetes
The lens will initially be developed to measure eye pressure in patients with glaucoma, but the pressure sensor can in principle be replaced by a biosensor, and this opens up for completely new application areas. According to Dr Moradi, it will be realistic within a few years to carry out both cancer detection and blood sugar measurements in diabetics via different biochemical markers in tear fluid.

“We’re preparing the lens with a thin channel that can guide tear fluid past the sensor, and this opens up for interesting new monitoring possibilities. We know that you can measure the glucose content of tear fluid, and we also know that there’s a correlation between certain forms of cancer and the content of a particular protein in tear fluid called lacryglobin. When the lens technology is ready, it will be able to work without a battery and provide data at short intervals, so we can gain access to a considerable amount of different health information via the eye,” says Dr Moradi.

PHOTO TOP: Associate Professor Farshad Moradi is an expert in designing nanocomputers with large memory capacity and very low power consumption. He and his PhD student Katrine Lundager will develop an eye contact lens for monitoring ocular pressure in glaucoma patients. (Photo: Lars Kruse)