[A simplified ultrasonographic measuring technic in combination with a computer program for calculating the power of...

In the last few years intraocular lens implantations have gained in popularity. In biometry new electronic methods have been introduced. For measuring the axial length by ultrasound we use the Ocuscan DBR 400 ST unit in combination with the digital storage system and an immersion technique. For lens power calculation we have developed a new computer program for a Commodore CBM 4032 using R.D. Binkhorst's formulae. In a series of 50 Kelman S-Flex anterior chamber lenses we found a mean error of +0.250 D and a standard deviation of +/- 0.662 D. Sixty-four percent of predictions were within the +/- 0.5 D range, and in 88% of these patients we predicted within the +/- 1.0 D range. The maximum errors of prediction were -1.0 D and +/- 1.75 D. Using an immersion technique an accurate axial length measurement can be obtained.