It’s a diagnostic technique still current and really useful for ophthalmic diseases. The traditional ultrasound exam is mandatory, for example, for the retinal exploration in case of advanced cataract, for the amplitude measurement of the iridocorneal angle and for the ocular muscles analysis. The most recent and innovative applications allow the use of the echographic signal for measuring the length of the eyeball, a fundamental step for calculating the artificial lens power before cataract surgery.