Comparison of Ultrasound and Optic Biometry with Respect to Refraction of Eyesafter Cataract Surgery

Overview

In theprospectivestudyof56patientswithcataract (67eyes)theauthorscomparedaxial length biometry) regarding to postoperative refraction of the eyes. Dioptricpower of the intraocular lens (IOL) was determined by SRK II. formula. Thedifference between predicted and actual postoperative refraction in the sphericalequivalent were compared 3 months postoperatively. Axial length measured byultrasound differed significantly from the axial length measured by optical biometry(p=0.016). Dioptric power of IOL calculated according to the axial lengthmeasured by ultrasound was significantly different from the dioptric power ofIOL calculated according to the axial length measured by optical biometry(p=0.003). The difference between predicted and actual postoperative refractionwas not statistically significant (p=0.384) even if we considered both type ofmeasurement. In conclusion, we found partial coherence interferometry was anaccurate and reproducible method for measurement of axial length of the eyebefore cataract surgery. In the cases of advanced dense cataracts backup ofultrasonic biometry is still necessary.

Key words:
cataract, ultrasound biometry, optical biometry, SRK II formula,predicted and actual postoperative refraction