This project is motivated by the potential benefits of continuous monitoring of the conditions inside the human eye for improved treatments of glaucoma.

Glaucoma is a condition in which the pressure inside the eye increases to levels that may damage the optic nerve and result in impairment or even loss of vision. Undesirable increase of pressure in the eye is due to an excess of fluid in the eye attributed to a malfunction in the body?s natural system for draining intraocular fluid. Increased pressure can damage the optic nerve and cause gradual vision loss. Over 65 million people are affected by glaucoma, and 4.5 million of these people are estimated to develop blindness in both eyes. Regular monitoring of intraocular pressure has the potential to help save the eyesight of millions of individuals afflicted by glaucoma. Pressure in the eye is known to change naturally throughout the day and is further influenced by environmental factors including body orientation and exercise. Continuous measurement of intraocular pressure may prove beneficial towards accurately assessing a patient?s risk and miniaturized medical implants have the potential to support this capability.

This project seeks to develop a device to be implanted in the eye that will be powered wirelessly, measure pressure with a transducer, and transmit the data to an external processor. The current device has a minimal size of 8mm x 3mm x 3mm, excluding an antenna with 20mm length, attained through the use of atomic-scale memory storage, miniscule pressure-sensing capacitors, and integrated circuits. In part due to its minimal size, the device requires minimal power, supplied by intentionally-radiated electromagnetic waves. The design incorporates a microsystem that includes a complementary metal-oxide-semiconductor (CMOS) microchip, interfaced with a minimally-sized pressure sensor. The microchip is capable of wirelessly transmitting information on pressure in the eye to a healthcare provider. It is hoped that this device will give ophthalmologists access to more representative intraocular pressure profiles such that they can more effectively tailor glaucoma treatments and reduce the number of people that will suffer from vision-loss due to glaucoma.

The figure above shows a complementary metal-oxide-semiconductor microchip that continuously processes the internal pressure of the eye (left). The monitoring capability offered by the device has the potential to warn patients at risk for glaucoma complications such that they can seek medical attention prior to losing their vision. The figure further demonstrates the proposed packaging and antenna for the chip, shown approximately to scale on a human iris (right).

• Project Researcher: Hansrai Bhamra