Comparison of axial length measurements in silicone oil–filled eyes using SS-OCT and partial coherence interferometry

Purpose: To compare axial length (AL) measurements in silicone oil (SO)-filled eyes using swept-source optical coherence tomography (SS-OCT) (the IOLMaster 700 and OA2000) and partial coherence interferometry (the IOLMaster 500). Setting: Zhongshan Ophthalmic Center, Guangzhou, China. Design: Cross-sectional study. Methods: We enrolled phakic patients who underwent SO removal surgery. The AL measurements by the IOLMaster 500, IOLMaster 700, and OA2000, both before and after SO removal, were compared. Multiple regression analysis was performed to identify risk factors for the differences between preoperative and postoperative AL measurements. Results: 68 patients (68 eyes) with a mean age of 46.43 ± 13.24 years were included. No statistically significant difference was observed in the preoperative AL measurements between the IOLMaster 500 and IOLMaster 700 (25.48 ± 2.51 mm vs 25.49 ± 2.46 mm; P = .63), whereas the OA2000 yielded shorter AL (25.34 ± 2.36 mm) (both P < .001). After SO removal, the AL measurements showed no statistically significant differences among the 3 devices. In reference to the postoperative AL, the IOLMaster 500 and IOLMaster 700 tended to overestimate the AL in SO-filled eyes (both P < .001), and this measurement error increased with longer AL (β = 0.08 and 0.05, respectively; both P < .001). No statistically significant difference was observed between preoperative and postoperative AL measurements by the OA2000 ( P = .18). Conclusions: The OA2000 is the preferred biometer for AL measurement in SO-filled eyes, whereas the IOLMaster 500 and IOLMaster 700 overestimate the AL especially for long eyes, which needs adjustment in clinical use.