<prompt> Which mode of ultrasound help is Orbital biometry?A- modeB-modeM-modeD-mode  <response>: A Mode Ultrasound is Amplitude Mode used for measuring Axial length of Eyeball and Orbital Biometry. A scan in Opthalmology is the A Mode Ultrasound. B mode is used in routine ultrasonography. M mode is used in chest and obstetric USG. D mode is used for vessels. 