CORNEAL TOPOGRAPHY FOR INTRAOCULAR-LENS POWER CALCULATIONS

BACKGROUND: In patients undergoing cataract extraction with PC IOL ins ertion, pre-op and postop corneal power measurement is necessary to ca lculate induced astigmatism, In cases with irregular corneal astigmati sm, measurements with traditional keratometry is inaccurate. We report the use of video keratography in three cases that required keratometr y readings in order to calculate IOL power, These cases were character ized by irregular or incomplete keratometer mires, so quantitative des criptors derived from computer-assisted corneal topography (TMS-1) wer e used instead, CONCLUSION: The standard keratometer is use less in ca ses in which the mires appear irregular or incomplete. In such eases, computer-assisted corneal topography can be used successfully. Recentl y, a new corneal topography index has been developed, the average corn eal power, which is a measure of the average corneal power within the entrance pupil. We are currently evaluating the use of average corneal power to assist in the calculation of IOL powers.