OBJECTIVE To determine whether alterations in architecture cause corneal biomechanical changes after simultaneous cataract surgery and limbal relaxing incisions (LRIs). METHODS Department of Ophthalmology, Kitasato University, Kanagawa, Japan. METHODS Observational case series. METHODS This study longitudinally assessed corneal hysteresis (CH) and the corneal resistance factor (CRF) using the Ocular Response Analyzer in eyes having cataract surgery with LRIs. The relationship between these biomechanical parameters and central corneal thickness (CCT), measured using an ultrasound pachymeter, was also assessed. RESULTS The mean CH was 10.0 mm Hg ± 1.2 (SD) preoperatively, 9.0 ± 1.6 mm Hg 1 day postoperatively, 9.7 ± 1.4 mm Hg at 1 week, 9.6 ± 1.4 mm Hg at 1 month, and 10.2 ± 1.3 mm Hg at 3 months. The mean CRF was 10.0 ± 1.5 mm Hg, 8.9 ± 1.6 mm Hg, 9.5 ± 1.5 mm Hg, 9.5 ± 1.4 mm Hg, and 9.5 ± 1.4 mm Hg, respectively. There were significant differences between preoperative and 1-day postoperative measurements (P=.005, CH; P=.004, CRF). The CH and CRF were significantly correlated with CCT (r = 0.33, P=.04 and r = 0.40, P=.01, respectively) 3 months postoperatively. CONCLUSIONS The CH and CRF values decreased 1 day after simultaneous cataract surgery with LRIs but soon recovered to preoperative levels, suggesting there were no significant changes in corneal biomechanical factors after 1 day. Corneal thickness may play a role in biomechanical factors even in such eyes.