WHAT IS EYE AND ORBIT ULTRASONOGRAPHY (EYE AND ORBIT ECHOGRAMS, EYE AND ORBIT SONOGRAMS) TEST?
Evaluation of the eye and orbit by the creation of an oscilloscopic picture from the echoes of high-frequency sound waves passing over the eye and eyelid (acoustic imaging). The time required for the ultrasonic beam to be reflected back to the transducer from differing densities of tissue is converted by a computer to an electrical impulse displayed on an oscilloscopic screen to create both a linear waveform and a two-dimensional dot-pattern picture of the structures. The B-scan mode is used to evaluate the optic disc, and the A-scan mode is used to evaluate optic nerve disease. Water immersion of the eye may also be used with the eye ultrasonogram to enhance images of the anterior part of the globe. The immersion of the transducer in water lifts it away from the eye, while still preventing air from obscuring the image. The transducer provides the best picture when it is at least 5-8 mm away from the structures being imaged. A newer method, ultrasound biomicroscopy, is able to provide even better images of the relationship of the structures of the anterior globe of the eye than conventional immersion ultrasonography.