Intraocular lens power calculation for microphthalmos.

PURPOSE

To evaluate the refractive results and accuracy of intraocular lens (IOL) power calculation formulas in eyes with microphthalmos.

SETTING

Department of Ophthalmology, Showa University Hospital, Tokyo, Japan.

METHODS

The accuracy of IOL power calculated using the SRK, SRK II, S-SRK, SRK/T, Holladay, and Hoffer Q formulas was evaluated in six eyes with axial lengths less than 19.0 mm.

RESULTS

Postoperative measurement of refraction showed a tendency toward hypermetropia compared with the refraction predicted by each formula. The best predicted refraction was calculated using the SRK/T formula. The tendency for hyperopic estimation was related to the axial length, particularly in eyes with a shorter axial length. However, there was no relationship between the refractive power of the cornea and the error in the predicted refraction by the SRK/T formula. Two eyes with an IOL power of 30.0 diopters (D) had severe hypermetropia.

CONCLUSION

Theoretical formulas were more accurate than empirical ones in eyes with microphthalmos. The severe hypermetropia in the two eyes with a 30.0 D IOL indicates that such patients require a higher IOL power.