PURPOSE: To evaluate the lens thickness, anterior cortex space, nucleus thickness, and posterior cortex space in cataractous eyes and compare them with those in eyes of younger patients with clear lenses. SETTING: Private practice, Lynwood, California, USA. DESIGN: Retrospective observational study. METHODS: The study evaluated a group of cataractous eyes and compared them with a group of eyes of younger patients with clear lenses. All measurements were performed with a biometer (Lenstar LS 900). RESULTS: The cataractous group (200 eyes) had a greater mean lens thickness (4.65 mm ± 0.41 [SD]) than the control group (80 eyes) (4.09 ± 0.33 mm). The mean measured values for the cataractous groups and control groups were 0.84 ± 0.21 mm and 0.35 ± 0.11 mm for anterior cortex space, 3.31 ± 0.25 mm and 3.27 ± 0.27 mm for mean nucleus thickness, and 0.51 ± 0.16 mm and 0.48 ± 0.13 mm for mean posterior cortex space, respectively. Anterior cortex space, nucleus thickness, and posterior cortex space correlated positively with lens thickness (r = 0.69, r = 0.69, and r = 0.59, respectively). Lens thickness, anterior cortex space, nucleus thickness, and posterior cortex space showed a weak inverse correlation with axial length (r = 0.06, r = 0.08, r = 0.10, and r = 0.10, respectively) and an inverse correlation with anterior chamber depth (r = 0.57, r = 0.43, r = 0.42, and r = 0.22, respectively). Lens thickness showed a positive correlation with age (r = 0.28), as did the anterior cortex space (r = 0.32) and posterior cortex space (r = 0.26), but nucleus thickness did not show a positive correlation (r = 0.02). CONCLUSION: Lens thickness increased with age and with cataract formation and was mostly attributable to an increase in the anterior cortex space. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.