[Transpalpebral measurement of axial eye length. Use of contact B-scan sonography].
In ophthalmology, it is very often necessary to determine the axial eye length. When standard measuring techniques fail, B-scan sonography may be used. However, coupling problems inhibit exact measurement. The aim of this study was to counter these problems. Correction values were created for the ultrasonic devices (1) Master-Vu (Sonomed), (2) CineScan (Quantel Medical), and (3) System-ABD (Innovative Imaging), including the position of the coupling layer of the hand pieces and the lid thickness. For evaluation of the method, the axial eye lengths of 35 eyes were measured transpalpebrally. These data were compared to those from the (4) IOL Master (Carl Zeiss Meditec). The usefulness of the developed method was shown by two patients. The correction values were (1) 3.0 mm, (2) 1.5 mm, and (3) 1.5 mm. The medial aberrations to (4) were (1) 0.4+/-0.5 mm, (2) 0.9+/-0.7 mm, and (3) 0.2+/-0.7 mm. The introduced method enables transpalpebral eye length measurement and is also applicable in cases of missing compliance or in eyes with an obfuscated optical medium.