Aims: To investigate the relationship between lens density measured with Pentacam Scheimpflug System and grading score using lens opacities classification system (LOCS III) as well as that between lens density and visual acuity in age-related nuclear cataract patients. Methods: Lens density and grading score were evaluated in 138 cases (180 eyes) with age-related nuclear cataract. LogMAR visual acuity was tested with ETDRS chart. The correlations between lens density value and LOCS III grading score and that between lens density value and LogMAR visual acuity were analyzed. Results: There was a linear increasing relationship between lens density value and LOCS III grading score in nuclear cataract patients. Lens density value had a stronger significant correlation with LOCS III NO score than that with NC score. Correlation between the nuclear lens density value and LogMAR visual acuity was stronger than that between NO score and LogMAR visual acuity or between NC score and LogMAR visual acuity. Conclusion: Lens density as a quantitative and objective parameter can present the degree of nuclear opacity and associated visual impairment due to nuclear cataract. LOCS III criterion as an economic cataract grading system provides data that are in satisfactory concordance with the results obtained by Pentacam Scheimpflug system.