PURPOSE: To quantify intraoperative stress levels in cataract surgeons and investigate the relationship between intraoperative stress and surgeon experience. SETTING: Department of Ophthalmology, Hanusch Krankenhaus, Vienna, Austria. DESIGN: Prospective, observational case series. METHODS: 5 ophthalmologists with surgery experiences of 70 to 15 000 previous surgeries volunteered for this study. Surgeons\' heart rate (HR) and heart rate variability (HRV) were measured during a total of 45 cataract surgeries. HR and HRV values were normalized to the minimal HR and maximal HRV of an overnight baseline measurement. The resulting normalized HR measure and HRV stress index are stress dependent and comparable between subjects. No case selection was performed. RESULTS: Less experienced surgeons showed higher HRV stress indices; differences between the surgeons with less than 180 and 500 surgeries and the 2 with 600 and 1500 surgeries, respectively, were statistically significant (alpha = 0.05). No statistically significant difference in stress indices was found between surgeons with 1500 and 15 000 surgeries, suggesting that there may be a plateau effect after 1500 surgeries. HRV stress indices and case times were negatively correlated with the logarithm of experience in the number of previously performed surgeries (r2 = 0.67 and 0.52). No significant stress buildup over multiple successive surgeries was found (alpha = 0.05). CONCLUSIONS: The new HRV stress index is a simple but powerful tool for quantifying intraoperative stress in cataract surgeons. Decreases in stress with increasing experience are congruent with previous works on general surgeons\' stress and follow a similar timeline as previously published, proficiency-based learning curves for cataract surgery.