Perioperative Low-Level Light Therapy for Ocular Surface Protection in Patients Undergoing Femto-LASIK: A Prospective Double-masked, Randomized Controlled Study

This multicenter, randomized, double-masked, sham-controlled clinical trial was conducted to evaluate the efficacy and safety of perioperative low-level light therapy (LLLT) in preventing dry eye disease (DED) symptoms in patients undergoing femtosecond laser-assisted in situ keratomileusis (Femto-LASIK). The study was performed between August 2024 and June 2025 at the Centro Vista Eye Clinic and the Cai Ferate Clinical Hospital (Iași, Romania) in accordance with the Declaration of Helsinki and institutional ethics approval.

Dry eye disease is a multifactorial condition characterized by tear film instability, ocular surface inflammation, and neurosensory abnormalities. It is among the most common complications after corneal refractive surgery, largely due to the transection of corneal nerves during flap creation and excimer laser ablation, which disrupts the lacrimal functional unit and reduces tear production. This can impair visual recovery and reduce patient satisfaction.

LLLT is a non-invasive photobiomodulation technique that delivers low-intensity, monochromatic red light (633 ± 10 nm) to periocular tissues. It has been shown to improve mitochondrial function, modulate inflammatory pathways, and enhance meibomian gland activity, with potential benefits in ocular surface disease. Its role in the perioperative management of DED after LASIK, however, has not been fully explored.

Eligible participants were consecutive adults (≥18 years) scheduled for Femto-LASIK. Exclusion criteria included pre-existing ocular surface disease or DED, prior ocular surgery, autoimmune disease, use of systemic medications associated with DED, and any intraoperative or postoperative complications that could interfere with evaluation. Both eyes of each patient were included in the analysis.

Participants were randomized (1:1) to receive either LLLT or sham treatment. LLLT was administered with the Eye-light® device (Espansione Marketing S.p.A., Italy) for 15 minutes one week before and one week after surgery. Sham-treated patients underwent the same procedure with less than 30% of the treatment power, ensuring masking. All surgeries were performed by experienced surgeons using standardized LASIK techniques under topical anesthesia, followed by a uniform postoperative regimen including topical antibiotics, corticosteroids, and preservative-free artificial tears.