A body-mountable device is provided to facilitate communication, via in-body electrical signals transmitted via electrodes of the body-mountable device into fluid of the body, with a smart pill located in a gastrointestinal tract of a body to which the body-mountable device is mounted or with some other device located within the body. The body-mountable device can be a contact lens or other eye-mountable device such that the electrodes of the eye-mountable device can transmit in-body electrical signals via tear fluid. The body-mountable device could transmit a command to the smart pill to dispense a drug into the body. The smart pill could transmit, via in-body electrical signals, an indication of a detected property of the gastrointestinal tract to the body-mountable device. A latency of transmission of signals between the body-mountable device and the smart pill could be used to determine the location of the smart pill within the gastrointestinal tract.

This disclosure relates to systems and/or methods for subtracting in the current domain an output current primary signal from a primary sensor from an output current reference signal from a reference sensor to produce a frequency output signal indicative of the difference between the output current primary signal and the output current reference signal.

An implantable intraocular physiological sensor for measuring a physiological characteristic, such as intraocular pressure. The implantable intraocular physiological sensor may include a tubular main body configured to house one or more electrical components. The implantable intraocular physiological sensor may also include a sensor cap configured to be inserted into a first end of the tubular main body with a moisture barrier seal. The implantable intraocular physiological sensor may wirelessly transmit measurements to an external device.

Apparatus, systems and methods employing contact lens sensors are provided. In some aspects, a contact lens includes a substrate that forms at least a portion of the body of the contact lens; an optical communication device disposed on or within the substrate; and a photodetector disposed on or within the substrate, wherein the photodetector harvests light emitted from a device and generates power from the harvested light. In some aspects, an apparatus comprises a tag having a circuit including: an optical communication device; and a photodetector that harvests light received and generates power from the harvested light. The tag can be disposed on or within a contact lens in various aspects.

An eye-mountable device including a lens including a polymeric material, the lens operable to be removably mounted over a corneal surface of an eye and to be compatible with a motion of an eyelid when the concave surface is so mounted; a sensor coupled to the lens and operable to provide output data indicative of whether an eyelid of an eye on which the lens is mounted is closed; and a display operable to display a light signal in response to the output data from the sensor that the eyelid is closed. A method including determining whether an eyelid of a wearer of an eye-mountable device is closed; and when an eyelid of a wearer is closed, sending a light signal from the eye-mountable device.

An eye-mountable device includes an electrochemical sensor embedded in a polymeric material configured for mounting in front of a surface of an eye. The electrochemical sensor includes a working electrode, a reference electrode, and a reagent that selectively reacts with an analyte to generate a sensor measurement related to a concentration of the analyte in a fluid to which the eye-mountable device is exposed. The working electrode can have at least one dimension less than 25 micrometers. The reference electrode can have an area at least five times greater than an area of the working electrode. A portion of the polymeric material can surround the working electrode and the reference electrode such that an electrical current conveyed between the working electrode and the reference electrode is passed through the at least partially surrounding portion of the transparent polymeric material.

In some aspects, an electronic contact lens for treating dry eye is presented. According to some aspects, the electronic contact lens includes a concave surface configured to conform to an eye of a patient, a sensor configured to generate a signal indicative of an eyelid movement, and at least one capacitor configured to store energy used for stimulating the eye. The electronic contact lens may further include at least two electrodes coupled to the at least one capacitor, wherein the at least two electrodes are exposed to the concave surface and configured to deliver power from the at least one capacitor to stimulate the eye. The electronic contact lens further includes a processor coupled to the sensor and electrodes. The processor may be configured to compute a blink rate from the sensor output, and, based on the blink rate, activate the at least two electrodes to stimulate the eye.

A body-mountable light sensing device includes a photodiode configured to receive light from a portion of subsurface vasculature and electronics configured to operate the photodiode to measure the received light. The electronics include a photodiode voltage source configured to reverse bias the photodiode, a current mirror, and a sigma-delta modulator configured to generate a digital output related to the received light and having a high resolution while using low power. The digital output could be used to determine a pulse rate or other properties of blood in the portion of subsurface vasculature by detecting absorption of ambient light by blood in the portion of subsurface vasculature. Components of the body-mountable device could be embedded in a polymeric material configured for mounting to a surface of an eye. The digital output and/or related information could be wirelessly communicated by the body-mountable device.

A method and system for extracting important signal information is disclosed. The method examines a group of signals obtained from testing of a patient's nervous system and finds a signal area of interest. Once a cluster of signals that all have the area of interest is found—the system concludes that the area of interest is located and validated. Signals that are not within the cluster are rejected and the signals within the cluster are signal-averaged to yield a signal-averaged waveform. The signal averaged waveform represents the results of the test.

A method of measuring ocular surface temperature includes steps as follows. Using a built-in temperature sensor called a black plate herein, an infrared heat sensor is provided and the temperature sensor contacts the black plate. The temperature sensor measures an actual black plate temperature. The infrared heat sensor detects a radiation emitted by the black plate, and the radiation is computed according to a temperature rising curve through a computing unit of a work station to generate a computed black plate temperature. A value of temperature shifting error is determined by subtracting the actual black plate temperature from the computed black plate temperature.