CRAO is considered a stroke of the eye. Studies show that about two-thirds of patients have underlying high blood pressure and one-fourth of patients will have significant carotid artery disease (plaque with narrowing of the artery lining), cardiac valvular disease or diabetes.
Electrical pressure is measured in volts, or voltage. All electrical devices are rated for specific voltages. Most devices and small appliances in a home are rated for 120 volts, while high-voltage appliances, such as electric dryers, ranges, and many baseboard heaters, are rated for 240 volts.
Power is the rate at which energy is transferred. It is not energy but is often confused with energy. The watt is the most commonly used unit of measure for power. It measures the rate of energy transfer. Click on a scenario number above to begin the interactive explainer. A watt equals a joule per second. If a smart phone uses five joules of energy every second, then the power of the phone is five joules per second, or five watts. The animation above demonstrates the difference between energy and power. Each slide in the animation will transfer energy at different rates for five seconds.