Effect of tear osmolarity on postoperative refractive error after cataract surgery

Purpose: To analyze the effects of tear osmolarity on postoperative refractive error and patient satisfaction after cataract surgery. Methods: The patients were divided into two groups based on the tear osmolarity (group Nr 1-normal tear osmolarity, <310 mOsm/L; group Nr 2-hyperosmolar, >310 mOsm/L). Preoperative and postoperative (1 month after surgery) visual acuities (VAs), refractions, and best corrected VAs (BCVAs) were measured. The postoperative refractive error was measured as the spherical equivalent (SE) (SE = sphere + [0.5 × cylinder]). The postoperative VA, BCVA, and SE were compared between groups. Results: Eighty-one patients were included in the study (group Nr 1=40 patients and group Nr 2=41 patients). The hyperosmolar group had a statistically significant higher postoperative refractive error (p<0.01, mean SE for group Nr 1=0.284; mean SE for group Nr 2=0.604) and lower VA after surgery (p<0.01, mean VA for group Nr 1=0.891; mean VA for group Nr 2=0.762). Conclusions: Increased tear osmolarity can affect the planned outcome of cataract surgery as an unexpected refractive error. Measuring tear osmolarity before routine cataract surgery would help achieve accurate results and improve postoperative patient satisfaction.