Video controlled M-mode biometry.

Abstract

To increase the accuracy of intraocular lens power calculation, an interface between an ultrasonic A-scanning device and a personal computer was created, allowing for an on-line interpretation of the ultrasonogram in an M-mode fashion. On the same computer display, a video recording of the movements of the transducer probe relative to the eye was inserted to obtain simultaneous information on the external alignment of the transducer probe. The precision of the experimental set-up in the measurement of intraocular distances was compared with conventional A-scanning procedures run in automatic mode. The video controlled M-mode biometry was found easy to operate and to result in reproducible axial length determination: The median value of the standard deviation was found to be below 0.04 mm as compared to a value of about 0.10 mm with conventional equipment. We concluded that video controlled M-mode biometry has great potential in the endeavour to increase the accuracy of intraocular lens calculation.