[Intraocular lens power calculation for short eye].

The accuracy of intraocular lens power calculation formulas for short eyes was examined. We examined 217 eyes with an axial length of shorter than 22.5 mm, with postoperative visual acuity of 0. 5 or more, and postoperative astigmatism of less than +/- 2D. Five formulas were tested for accuracy in prediction for postoperative refraction, the S-SRK, the SRK, the SRK II, the SRK/T, and the Binkhorst formulas. The best results were produced by the S-SRK formula which predicted 74% of the cases within +/- 1D error, if the axial length was shorter than 22 mm. The A-constant was also examined to study the effect of postoperative refraction. The A-constant takes into consideration the depth of the anterior chamber lens, so that the differences in depth would be influenced for short eyes rather than regular eyes in prediction. However, there was no significant difference among the different A-constant groups.