Abstract: A device provides remote ophthalmic examinations and includes one, plural or all of the following capabilities: slit lamp examinations, visual acuity examinations, fundoscopy, and eye pressure assessment. Preferred devices enable a patient to self-align or adjust device themselves without the help of a professional, collect and store data and can transmit data when a connection is available to a professional or an analysis system, such as a machine learning system, for evaluation.

Abstract: A lighting device has one or more light sources; a primary input power connection; and electronic circuitry for controlling delivery of power from the primary input power connection to the one or more light sources. The electronic circuitry determines an indication of an external electrical loading on a primary power supply network coupled, in use, with the primary input power connection the circuitry varies the power drawn from the primary input power connection in dependence upon the determined indication of the external electrical loading on the primary power supply network. In this way, during times of high demand on the primary supply network, the lighting device can reduce the amount of power drawn from the primary supply.

Abstract: In one embodiment of lighting devices and lighting systems, the lighting device has a connection for connecting to a primary power supply and has a secondary power supply, such as a battery. A measuring circuit is operable to measure an impedance of the primary power supply connection and to determine from the measurement if a main power supply has failed, and if so whether to power light sources using power from the secondary power supply.

Abstract: In one embodiment of lighting devices and lighting systems, the lighting device has a connection for connecting to a primary power supply and has a secondary power supply, such as a battery. A measuring circuit is operable to measure an impedance of the primary power supply connection and to determine from the measurement if a main power supply has failed, and if so whether to power light sources using power from the secondary power supply.

Abstract: In one embodiment of lighting devices and lighting systems, the lighting device has a connection for connecting to a primary power supply and has a secondary power supply, such as a battery. A measuring circuit is operable to measure an impedance of the primary power supply connection and to determine from the measurement if a main power supply has failed, and if so whether to power light sources using power from the secondary power supply.

Abstract: In one embodiment of lighting devices and lighting systems, the lighting device has a connection for connecting to a primary power supply and has a secondary power supply, such as a battery. A measuring circuit is operable to measure an impedance of the primary power supply connection and to determine from the measurement if a main power supply has failed, and if so whether to power light sources using power from the secondary power supply.

Abstract: A lighting device has one or more light sources; a primary input power connection; and electronic circuitry for controlling delivery of power from the primary input power connection to the one or more light sources. The electronic circuitry determines an indication of an external electrical loading on a primary power supply network coupled, in use, with the primary input power connection the circuitry varies the power drawn from the primary input power connection in dependence upon the determined indication of the external electrical loading on the primary power supply network. In this way, during times of high demand on the primary supply network, the lighting device can reduce the amount of power drawn from the primary supply.

Abstract: A system and method of operation for a distributed media network and meta data server provides a low cost, efficient, reliable and versatile alternative to traditional media network systems. Multiple media data file servers are designated as primary or alternate data file servers for different media data media files. Related or linked media data files may be distributed throughout a media network which results in lower peak bandwidth usage at each media data file server. Each server in the distributed media network responds more quickly and efficiently due to its limited functionality and scope of media data files that it must server. Media data file servers transfer low bandwidth meta data to client devices allowing a significant increase in the number of clients which can simultaneously log in to a dedicated network server.