A New B-Scan System for Ophthalmic Diagnosis

A B-scan apparatus is presented comprising a mechanical scanning system, an electronic pulse shaping device, and a storage oscilloscope. The apparatus enables 90° arc-scan and sector scan, linear scan, linear-arc compound scan, and linear-sector compound scan. The various scan modes are motor driven. Several manipulators can be used to adjust the radius of the arc scan and sector scan, the distance of the centre of rotation to the eye, and the position of the mechanical system with respect to the eye, respectively. The whole system can be rotated around the centre of rotation of the arc scan and sector scan, so various cross-sections of the eye and the orbit can be obtained without further adjustments. A singular scan takes about 8 sec. The electronic system consists of a differentiator with negative capacitance coupling, and a level sensitive generator which delivers 0.2-μsec standard pulses. The patient is in supine position and acoustic coupling is obtained by means of a bassin filled with saline solution. The bassin is made of adhesive plastic drape that is fixed to the face and clamped around a metal ring.