title: Echo reference standards in ophthalmic ultrasonography.
abstract: The use of different echo standards in ophthalmic ultrasonography is discussed. The acoustical properties of the W38 Hema reflector made out of soft corneal contact lens material are determined and verified in several independent measurements. It is shown that this material meets the requirements for plane echo interfaces which are mandatory for reflectors considered to serve as echo standards. A conversion diagram is given for echo references presently used in ophthalmic ultrasonography. Finally, an example for an application of the W38 reflector in performance control and calibration measurements on ultrasonic instruments is presented.
mesh_terms: D002138:Calibration; D003263:Contact Lenses, Hydrophilic; D006801:Humans; D008954:Models, Biological; D008961:Models, Structural; D009885:Ophthalmology / Q000295:instrumentation / Q000592:standards*; D012015:Reference Standards; D014463:Ultrasonography / Q000295:instrumentation