Clinical prediction versus ultrasound measurement of IOL power.

1. Clinical prediction was better than ultrasound prediction for the first 20 cases. It was approximately equal for the next 20 cases, but after this ultrasound was the more accurate. 2. There was no significant difference in ability of either clinical prediction of ultrasound to predict the power of various types of lenses, namely, 4-loop intracapsular lenses, 2-loop extracapsular lenses and Choyce-style anterior chamber lenses. 3. There was no clinically significant difference in accuracy of prediction regardless of the source (manufacturer) studied in this series. 4. Two major factors affecting results which ultrasound is totally helpless in predicting are surgically induced astigmatism and accuracy of stated lens power supplied.