Ultrasonography offers the clinician a safe, noninvasive, dynamic tool with instant feed-back for evaluation of vitreoretinal disorders. Ultrasonography was first applied in ophthalmology in 1956 by Mundt and Hughes. They used time amplitude-mode (A-scan) to evaluate an intraocular tumor. Ultrasound wave has frequencies greater than 20-KHz (i. e. 20, 000 oscillations/sec), rendering them inaudible to humans. The machine uses frequency in the range of 8 to10 MHz. These high frequency and short wavelength waves allow minute resolution of ocular and orbital structures. Ultrasound is propagated as a longitudinal wave that consists of alternating compressions and rarefactions of molecules as the wave passes through a medium. Velocity of the ultrasound wave is dependent on the medium through which it passes. Ultrasonography uses the system in which the piezoelectric crystal, located near the face of the probe, produces ultrasound waves. It emits ultrasound waves and then detects and processes the returning echos. A and B-scan are the important ultrasound displays being used in ophthalmology. A-scan echography consists of representation of echos in a one-dimensional display where spacing between the vertical spikes denotes time required by the wave to reach and come back from interface. B-scan echography consists of a two-dimensional display i. e. using both the vertical and horizontal displays to denote location and configuration. It yields information primarily about the topographic nature of intraocular and orbital structures and lesions. Standardized echography uses a combined A-scan and B-scan. A-scan is usually done after the pathology has been detected with B-scan. A-scan is used to measure the size of the lesion in various directions. All B-scan probes have a marker. The upper part of the scan represents the position of the marker in relation to globe. Methylcellulose is applied to the probe as a coupling medium. The probe can be placed on conjunctiva or cornea. Quantitative topography is performed to determine the reflectivity, internal structure, and sound attenuation of the lesion. The retina in the normal eye appears on B-scan ultrasonography as a smooth, concave, acoustically opaque surface formed by echoes arising from the vitreoretinal interface.