American History of IOL Power Calculation

The history of ultrasound axial length measurement and formula development for IOL power calculation in America are described beginning with the initial trials in April 1974, and through the trials and tribulations the author experienced in trying to improve the accuracy of the procedure through instrumentation and formulas as well as efforts to teach others how to perform it and improve it. This includes the first studies showing the sound velocities of the eye, the normal biometric measurements of the cataractous eye, and the development of the first calculators and computer programs for using the formulas.