Keratorefractive Lenticule Extraction (KLEx) Surgeries and Dry Eye: A Narrative Review of Predominantly Small Incision Lenticule Extraction-Based Evidence

Keratorefractive lenticule extraction (KLEx) is the newest widely adopted flapless refractive procedure. Small incision lenticule extraction (SMILE) accounts for most of the available evidence on postoperative dry eye, whereas evidence for newer KLEx platforms remains limited. This narrative review summarizes changes in dry eye symptoms, tear film parameters, corneal sensitivity, and corneal innervation after KLEx, as well as factors associated with postoperative dry eye and available treatment strategies. Most studies reported an early postoperative worsening of dry eye symptoms and tear film stability, followed by gradual recovery, usually within 3–6 months. Changes in tear production were less consistent. Compared with laser-assisted in situ keratomileusis, SMILE showed better preservation and earlier recovery of corneal sensitivity and innervation. However, the differences in dry eye symptoms and tear film parameters were less consistent among studies. Several treatments targeting different aspects of postoperative dry eye have been studied after KLEx, but the supporting evidence varies between interventions.