[Current scanning and biometry equipment in ophthalmologic ultrasound diagnosis]

The development of ophthalmological sonographic equipment started as early as 1958 with the ultrasonic "slit lamp" of Baum and Greenwood. This was an immersion-type device with a closed membrane. Subsequent developments took place mainly after the introduction of the contact B-scanner by Bronson and Turner approximately 10 years ago. The instrument designed by them still serves as a source of inspiration for the creation of many "small-part" scanners. Among the special display modes featured in ophthalmological equipment, we have the deflection-modulated B-image (AB-mode) and the so-called "continuous-vector" mode for the A-trace selection from a real time B-mode image. Other examples are the specially designed A-mode equipment for measurement of the axial length of the human eye, and the A-mode equipment with a more or less standardized-gain characteristic curve of the overall amplification.