Contact lens for continuous IOP monitoring

Glaucoma, affecting about 4% of the population over 40 years of age, is an asymptomatic, progressive and irreversible disease which leads to blindness unless adequate treatment is provided early on. Static measurements currently performed by ophthalmologists during office hours do not permit widespread and cost-effective monitoring of dynamic intraocular pressure changes responsible for optic nerve damage.

The need for continuous monitoring of glaucoma patients has been recognized since several years. Diurnal fluctuations in IOP represent an independent risk factor for glaucoma disease progression despite normal office IOP. A significant percentage of glaucoma patients have intraocular peaks or target pressure breathroughs at night or early morning.

Sensimed AG, a Swiss medical devices company, has developed a novel solution to monitor intraocular pressure continuously up to 24 hours. The solution consists of a soft, non-invasive contact lens which encapsulates a telemetric sensor. The external system consists of an adhesive antenna worn around the eye attached to a portable recording device.

SENSIMED Triggerfish^® – Continuous IOP Monitoring

SENSIMED, with its revolutionary SENSIMED Triggerfish^® tool for continuous monitoring of fluctuations in intraocular pressure, will not only revolutionize the way glaucoma is diagnosed and treatment is performed, but will also make a contribution to a deeper understanding of its progression. For the first time it will allow ophtalmologists to personalized the patient’s treatment and to monitor the efficacy of the treatment.

The SENSIMED Triggerfish^® Sensor is a soft hydrophilic single use contact lens, containing passive and active strain gauges embedded in the silicone to monitor fluctuations in diameter of the corneoscleral junction. The output signal sent wirelessly to the SENSIMED Triggerfish^® Antenna is directly correlated to fluctuations in intraocular pressure. The adhesive Antenna, worn around the eye is connected to a portable Recorder through a thin flexible Data Cable.

The patient wears the SENSIMED Triggerfish^® up to 24 hours and assumes normal activities including sleep periods. When the patient returns to his doctor, the data is transferred from the Recorder to the practitioner’s computer via Bluetooth technology for immediate analysis.

SENSIMED Triggerfish^® is a breakthrough solution to continuously monitor fluctuations of intraocular pressure. The SENSIMED Triggerfish^® is currently available only to selected and closely controlled centers in Europe.

Not yet approved for sale in the U.S.A.

The SENSIMED Triggerfish^® advantages in daily practice:

• Non-invasive and convenient
• Monitoring IOP continuously up to 24 hours
• Recording during sleep and normal activities
• Ambulatory or in-hospital use
• Enables early diagnosis and personalized treatment

Technology

Sensimed has developed a full, generic telemetry solution which can be adapted to interface various types of sensors for a variety of applications. The goal is to enable in-situ measurement without physical connection nor battery supply on the sensing site. An external system will send radio-frequency power (Energy) to the sensing site and receive in return measurement information (Data), similarly to RFID technology with the difference that the purpose is not to retrieve an ID, but the real-time measurement performed by the in-situ sensor.

SENSIMED Technology includes design, manufacturing and production of microelectromechanical systems (MEMS) as well as miniaturized assembly encapsulated in silicone for medical applications.

Article by G.T. Georgopoulos, MD
Assoc. Professor of Ophthalmology
Athens University Medical School