Comparative Study Evaluating the Post Phacoemulsification Refractive Predictive Accuracy Using Sirius+ Scheimpflug Tomography and Nidek Optical Biometer AL-Scan

Abstract Background IOL power calculation is now a crucial step in cataract surgeries especially after development of phacoemulsification and intraocular lens as the aim of cataract surgery now is no longer media opacity treatment only but also correction of refraction errors. That’s why new devices with new techniques as Sirius Scheimpflung tomography which combines both Scheimpflug camera and placido disk corneal topography and uses ray tracing method and artificial intelligence in IOL power calculation was evolved to increase the accuracy of IOL power calculation. Purpose Compare the accuracy of predictability of postoperative refraction of Sirius + (CSO, Italy) Scheimpflung tomography with Nidek optical biometer AL-scan (Nidek CO., Tokyo, Japan). Materials and Methods Forty eyes of twenty eight patients were enrolled in this prospective cohort comparative study, which was performed at the Department of Ophthalmology of Ain Shams University Hospitals during the period between April 2023 till December 2023. The patients underwent complete ophthalmological examination and did biometry with both Sirius tomography and Nidek optical biometer, then postoperative refraction was done using autoref (Shin-Nippon accuref 8001, Japan. Comparison between predicted refraction by Sirius and Nidek with postoperative refraction was done. Results There was statistically significant difference between the Nidek postoperative predictive refraction and the postoperative spherical equivalent of the studied patients with p-value < 0.05, while there was statistically non-significant difference between the Sirius postoperative predictive refraction and the postoperative spherical equivalent with p-value > 0.05. Conclusion Sirius tomography is more accurate in IOL power calculation than Nidek optical biometry.