To evaluate the effects of lubricating eye drops on the repeatability of keratometry (K) measurements in patients presenting for cataract surgery

Purpose – To evaluate the impact of lubricating eye drops on the repeatability of keratometry (K) measurements in cataract surgery patients. Design – Prospective, comparative, hospital-based study. Method – Keratometry was performed using an autorefractometer. At Visit 1, baseline K readings were taken twice before instilling drops. After instillation, K readings were recorded at 30 seconds and 2 minutes. Tear Break-Up Time (TBUT) was measured to classify patients into normal and dry eye groups. A second set of readings was taken the following morning. At Visit 2, one week postoperatively, a third set of K1 and K2 readings was recorded. Result – Variations in K1 and K2 readings were analyzed across time points and between tear film groups. In the dry eye group, significant changes in K1 were observed across intervals (p < 0.0001). Significant differences in K1 were also found between normal and dry eyes at 30 seconds and 2 minutes post-instillation. For K2, notable differences occurred in both groups, particularly between pre- and postoperative readings and all intervals in the dry eye group. Conclusion – Lubricating drops significantly affect keratometry, especially in dry eyes. Waiting over 5 minutes post-instillation is advised before taking measurements.