Comparison of early postoperative dry eye after KLEx and FS-LASIK: a contralateral eye study

OBJECTIVE: To compare early postoperative dry eye outcomes in contralateral eyes of the same patients undergoing Keratorefractive Lenticule Extraction (KLEx) versus Femtosecond Laser-Assisted Laser In Situ Keratomileusis (FS-LASIK), with tear film osmolarity defined as the primary outcome measure. METHODS: system. Secondary outcome measures included tear break-up time (tBUT) and subjective symptoms assessed via the Ocular Symptom Questionnaire Scores (OSDI). RESULTS: A total of 34 eyes of 17 patients (7 females and 10 males) were evaluated. Group 1 (KLEx) included 17 eyes and group 2 (FS-LASIK) included contralateral 17 eyes. The mean postoperative follow-up period was 34.2 days. Mean tear osmolarity was 297.7 ± 8.3 mOsm/L in the group 1 and 315.3 ± 10.2 mOsm/L in the group 2 (p < 0.001). Mean tBUT was 10.3 ± 3.1 s for group 1 and 7 ± 2.32 s for group 2 (p < 0.001). The mean postoperative OSDI scores were 32.5 for group 1 and 42 for group 2, with a preoperative baseline of 10.2 (both groups; p < 0.001). CONCLUSIONS: KLEx demonstrated superior early postoperative ocular surface stability compared to FS-LASIK in contralateral eyes. The procedure resulted in significantly less tear hyperosmolarity and better subjective comfort, suggesting it may be a preferable surgical option for minimizing dry eye induced by corneal refractive surgery.