Background：To compare the clinical performance of bifocal and trifocal intraocular lenses (IOLs) in cataract surgery, a meta-analysis on randomized controlled trials was conducted. Methods: A comprehensive literature retrieval of PubMed, Science Direct and EMBASE was performed in this systematic review. Clinical outcomes included visual acuity (VA), contrast sensitivity (CS), spectacle independence, postoperative refraction and surgical satisfaction. Results: There were 8 RCTs included in this study. The difference of uncorrected near VA (UNVA) between the bifocal IOLs and trifocal IOLs had no clinical significance [MD=-0.01, 95%CI: (-0.02,0.00)]. There was no significant difference in the distant-corrected near VA (DCNVA) with MD of 0.04 [95%CI (-0.02, 0.10)]. Compared with trifocal group, the uncorrected intermediate visual acuity (UIVA) [MD=0.09,95%CI:(0.01,0.17)] was significantly worse in the bifocal group. No difference was found in distance-corrected intermediate VA(DCIVA) [MD= 0.09, 95%CI: (-0.04, 0.23)] between two groups. Analysis on AT LISA subgroup indicated the bifocal group had worse intermediate VA than trifocal group (AT LISA tri 839M) [MD= 0.18, 95%CI: (0.12, 0.24) for UIVA and MD= 0.19, 95%CI: (0.13, 0.25) for DCIVA]. However, there was no statistically significant difference between the two groups in the uncorrected distance VA(UDVA) and corrected distance visual acuity (CDVA) [MD=0.01, 95%CI: (-0.01,0.04) for UDVA; MD=0.00, 95%CI: (-0.01,0.01) for CDVA]. The postoperative refraction of bifocal group was similar to that of trifocal group [MD=-0.08, 95% CI: (-0.19, 0.03) for spherical equivalent; MD=-0.09, 95%CI: (-0.21, 0.03) for cylinder; MD=-0.09, 95% CI: (-0.27, 0.08) for sphere]. No difference was found for spectacle independence, posterior capsular opacification (PCO) incidence and patient satisfaction between bifocal IOLs and trifocal IOLs. [RR=0.89, 95% CI: (0.71, 1.12) for spectacle independence; RR=1.81, 95% CI: (0.50, 6.54) for PCO incidence; RR=0.98, 5% CI: (0.86, 1.12) for patient satisfaction]. Conclusion: Patients receiving trifocal IOLs, especially AT LISA tri 839M, have a better intermediate VA than those receiving bifocal IOLs. Near and distance visual performance, spectacle independence, postoperative refraction and surgical satisfaction of bifocal IOLs were similar to those of trifocal IOLs. Keywords: bifocal; trifocal; intraocular lenses; cataract surgery; randomized; IOLs; meta-analysis.

Rationale and Objectives: To test whether higher iodine concentration together with higher noise level could lead to a further dose reduction in an already low dose coronary CT angiography (CCTA) protocol without comprising image quality. Materials and Methods: One hundred eighty patients with suspected coronary artery disease (CAD) were randomly assigned into three groups: (a) conventional dose (CD) group, 100 kV with a noise index (NI) of 25 and iohexol (350 mg I/ml); (b) low dose (LD) group, 80 kV with a NI of 25 and iohexol (350 mg I/ml); (c) further low dose (FLD) group, 80 kV with a NI of 30 and iomeprol (400 mg I/ml). The volume and injection rate of contrast medium were fixed at 60 ml and 5 ml/s. The radiation dose (volume CT dose index [CTDIvol], dose length product [DLP], and effective dose [ED]) were recorded. For image quality, both quantitative (enhancement, noise, signal-to-noise ratio [SNR], and contrast-to-noise ratio [CNR]) and qualitative indices were assessed. Results: Compared to the CD group, ED was reduced by 16% and 42% in the LD and FLD groups, respectively (p < 0.05). Qualitative analysis showed no significant difference among the 3 groups (p > 0.05), while quantitative analysis revealed significantly higher attenuation in the LD and FLD groups. Signal-to-noise ratios and CNRs of the LD and FLD groups were significantly higher except for the CNR at the left circumflex branch of the FLD group (p < 0.05). Conclusion: Increasing iodine concentration and noise level may further reduce the radiation dose by 26% on top of a 16% reduction from 100 kV to 80 kV without image quality compromise.

Background：To compare the clinical performance of bifocal and trifocal intraocular lenses (IOLs) in cataract surgery, a meta-analysis on randomized controlled trials was conducted. Methods: A comprehensive literature retrieval of PubMed, Science Direct and EMBASE was performed in this systematic review. Clinical outcomes included visual acuity (VA), contrast sensitivity (CS), spectacle independence, postoperative refraction and surgical satisfaction. Results: There were 8 RCTs included in this study. The difference of uncorrected near VA (UNVA) between the bifocal IOLs and trifocal IOLs had no clinical significance [MD=-0.01, 95%CI: (-0.02,0.00), p=0.97]. There was no difference for the distant-corrected near VA (DCNVA) with MD of 0.01[95%CI (-0.02, 0.05), p=0.86]. Compared with trifocal group, bifocal group showed a significantly worse uncorrected intermediate visual acuity (UIVA) [MD=0.09,95%CI:(0.01,0.17), p＜0.01]. No difference was found in distance-corrected intermediate VA(DCIVA) [MD= 0.09, 95%CI: (-0.04, 0.23) , p＜0.01] between two groups. For the AT LISA group, the subgroup analysis also indicated the bifocal group had worse intermediate VA than trifocal group (AT LISA tri 839M) [MD= 0.18, 95%CI: (0.12, 0.24), p=0.35 for UIVA and MD= 0.19, 95%CI: (0.13, 0.25), p=0.21 for DCIVA]. However, there was no statistically significant difference between the two groups in the uncorrected distance VA(UDVA) and corrected distance visual acuity (CDVA) [MD=0.01, 95%CI: (-0.01,0.04), p=0.51 for UDVA; MD=0.00, 95%CI: (-0.01,0.01), p=0.94 for CDVA]. The postoperative refraction of bifocal group was similar to that of trifocal group [MD=-0.08, 95% CI: (-0.19, 0.03), p=0.51 for spherical equivalent; MD=-0.09, 95%CI: (-0.21, 0.03), p=0.78 for cylinder; MD=-0.09, 95% CI: (-0.27, 0.08), p=0.28 for sphere]. No difference was found for spectacle independence, Posterior capsular opacification (PCO) incidence and patient satisfaction between bifocal IOLs and trifocal IOLs. [RR=0.89, 95% CI: (0.71, 1.12), p=0.69 for spectacle independence; RR=0.81, 95% CI: (0.74, 1.15), p=0.65 for PCO; RR=0.98, 5% CI: (0.86, 1.12), p=0.97 for satisfaction]. Conclusion: Patients receiving trifocal IOLs have a better intermediate VA than bifocal IOLs, especially for the AT LISA subgroup. Near and distance visual performance, spectacle independence, postoperative refraction and surgical satisfaction of bifocal IOLs were similar to those of trifocal IOLs.