Purpose:1. To evaluate posterior segment of diabetic patient with dense cataract preoperatively using B-scan ultrasonography.2. To find the efficacy of B-scan ultrasonography in evaluating posterior segment by comparing B-scan findings with that of the post-operative fundoscopy.Design:A hospital based prospective observational study conducted in 202 diabetics with dense cataract, at HIMS during December2017 to May2019. Patients with ocular trauma, corneal pathology, uveitis, glaucoma, intraop complications like posterior capsular rent, iris prolapse, iridodialysis, capsular dialysis and complicated cataract like pathological myopia, retinitis pigmentosa were excluded from the study. Preoperative B-scan ultrasonography performed to evaluate posterior segment. They underwent manual SICS with PCIOL implantation under PBB. Postoperatively followed up at 1 week, vision and dilated fundoscopy to evaluate posterior segment. Fundoscopy was compared with preoperative B-scan report and the efficacy of B-scan was analyzed.Results:Among 202 eyes, B-scan in 129 (63.9%) normal, 24.8% had age related vitreous changes, only 11.3% of the patients had Proliferative diabetic Retinopathy. Among the patients with normal B-scan, postoperative fundoscopy was normal in 75.2% patients and DR changes and macular edema in 24.8% of the patients with normal B-scan.Conclusion:B-scan is effective in evaluating posterior segment and helps in providing visual prognosis. Though B-scan is helps in assessing the approximate visual prognosis, DR changes and macular edema in 24.8% of the patients with normal B-scan which could be the cause for low vision postoperatively. Thus, guarded visual prognosis has to be explained to all the diabetic patients with dense cataracts preoperatively.