Comparison of the Postoperative Refractive Errors Measured by Ultrasound and Partial Coherence Interferometers after Phacovitrectomy

ABSTRACT

PURPOSE: To compare the accuracy of refractive outcome measured by Ultrascan(R) (Alcon, Fort Worth, TX, USA) and partial coherence interferometers after phacovitrectomy. METHODS: We performed a retrospective study in 74 eyes of 74 patients who underwent phacovitrectomy. SRK-T formula was used to predict intraocular lens (IOL) power. The difference between the predicted and postoperative refractive outcomes for the 2 methodologies (Ultrascan(R) and IOL Master(R) [Zeiss, Carl Zeiss, Jena, Germany]) were compared. The predicted refractive outcome was defined as the estimated refractive error when the selected IOL was inserted. RESULTS: The axial length measured using IOL Master(R) was statistically longer than when measured using Ultrascan(R) (23.85 +/- 0.15 mm, 23.56 +/- 0.15 mm, p < 0.001). Based on keratometry, statistically significant difference between the 2 groups was not observed. The postoperative refractive error was more accurate when using the IOL Master(R) than Ultrascan(R) (0.08 +/- 0.74, 0.47 +/- 0.69, p < 0.001). However, in cases of vitreous hemorrhage, the postoperative refractive error was 0.42 +/- 0.49 with the IOL Master(R) and 0.07 +/- 0.54 with the Ultrascan(R). CONCLUSIONS: Generally, IOL Master(R) is a more accurate method for calculating the IOL power prior to phacovitrectomy. However, in cases of vitreous hemorrhage, Ultrascan(R) appears superior to IOL Master(R) when calculating the IOL power.