Abstract
PURPOSE: To compare the accuracy of isolated manual marking and smartphone-assisted manual marking with the Verion image-guided system for toric intraocular lens (IOL) implantation. METHODS: In this prospective observational study, 42 eyes of 36 patients planned for phacoemulsification with toric IOL implantation with corneal astigmatism >1D as measured on Lenstar LS 900 optical biometer were included. Patients were preoperatively registered and photographed on the Verion image-guided system. In the operating room, the patient's eye was manually marked at the 6 o' clock limbus (Manual axis-90°) on slit-lamp in sitting position. Next, using the smartphone android app-iToric Patwardhan, the exact mark axis was confirmed (Smartphone axis). Following this, the patient was taken on the operation table where the mark axis was confirmed with Verion digital overlay on an external screen (Verion axis). The absolute angular deviation of manual axis from Verion was compared with the absolute angular deviation of the smartphone axis from Verion as the primary outcome measure. RESULTS: The mean absolute angular deviation between the smartphone axis and the Verion axis was 2.62°, which was significantly lower (P < 0.05) than that between the manual axis and Verion axis (4.60°). Moreover, the intraclass correlation coefficient between the smartphone axis and Verion axis was 0.88 indicating a strong agreement between the two. CONCLUSION: Smartphone-assisted manual marking significantly improves the accuracy of manual marking alone when comparing with the Verion Digital Marker system for toric IOL implantation.