We live and practice ophthalmology in an era of sophisticated imaging techniques: computed tomographic (CT) scanning and CT angiography, magnetic resonance (MR) imaging and MR angiography, and digital subtraction angiography. All of these procedures can be helpful to the physician dealing with ocular and orbital disease, but none is more useful than ophthalmic ultrasound , It is the only method of determining the optimum intraocular lens power for a patient about to undergo cataract surgery, it provides an accurate representation of tissue status in patients with opaque media, and it is crucial in the investigation of patients with clinical evidence of orbital disease.In my opinion, it is the most sensitive test for thyroid eye disease, it can often provide a tissue-specific diagnosis of an orbital mass, and it can accurately assess the diameter of the optic nerve and provide evidence of whether enlargement of the nerve is caused by a solid process or surrounding fluid. the technique is extremely operator dependent. One cannot evaluate the results of a B-scan (let alone an A-scan!) as one does a CT scan or MR image. The key is having a superb, experienced ultrasonographer .ophthalmic ultrasound remains an integral part of ophthalmology practices around the world. Its role continues to be in the diagnosis and management of a wide variety of ocular and orbital disorders. Understanding both diseased and healthy ocular structures, as well as mastering the prescribed examination techniques, remains an essential task for echographers, no matter what their level of expertise may be.