Intraocular lens power calculations: the optimal approach.

The differences were studied between retrospectively calculated emmetropizing intraocular lenses and lenses estimated from different methods and formulas, either with or without the use of ultrasonic biometry. A number of 201 eyes was involved. The results show that ultrasonic biometry is an indispensable tool for the prediction of the power of intraocular lenses, which would produce emmetropia. The best results were obtained when using biometry and the simple empirical SRK formula.