Accuracy and reliability of IOL master and A-scan immersion biometry in silicone oil-filled eyes

Purpose To compare the accuracy and reliability of intraocular lens (IOL) master and A-scan immersion biometry in silicone oil (SO)-filled eyes. Methods A prospective, consecutive, nonrandomized study was performed in 34 SO-filled eyes of 34 patients, who underwent a pars plana vitrectomy, with SO removal and cataract surgery, as well as IOL implantation. Both IOL master and immersion A-scan were performed to measure the axial length (AXL) before SO removal. Three months after removal of the SO, AXL measurements using IOL master and refraction was performed. Accuracy of the two techniques was determined by a mean postoperative AXL using an IOL master and reliability was determined by mean actual postoperative refractive error. Results Preoperative mean AXL was 23.91 +/- 0.24mm (range 21.33-28.61 mm) and 23.71 +/- 0.59mm (range 19.27-36.18 mm) by IOL master and A-scan immersion, respectively. Postoperative mean AXL by IOL master was 23.90 +/- 0.23 mm (range 21.58-27.94 mm), which showed a statistically significant difference from the preoperative mean AXL by A-scan immersion (P = 0.005). The AXL measurement by IOL master also was more accurate than A-scan immersion by Pearson's correlation (0.966 vs 0.410). For reliability of the two techniques, the predictive postoperative refractive error in A-scan immersion (mean 1.79 +/- 1.04 D, range - 14.62 to 16.41 D) was greater than that in IOL master (mean 0.60 +/- 0.23 D, range - 2.74 to 2.33 D), with a statistically significant difference (P = 0.049). Conclusion IOL master had more accuracy and less deviation in predictive postoperative refractive error than A-scan immersion in SO-filled eyes. Eye (2012) 26, 1344-1348; doi:10.1038/eye.2012.163; published online 10 August 2012