Effect of Low-Level Light Therapy on Ocular Surface Parameters in Patients Undergoing Femto-Lasik Surgery

The intervention consists of non-invasive periocular photobiomodulation using the Eye-light® device (Espansione Marketing S.p.A., Italy), which delivers low-level monochromatic red light (633 ± 10 nm) through a specially designed mask. Participants receive two 15-minute sessions, one 7 days before and one 7 days after femtosecond laser-assisted in situ keratomileusis (Femto-LASIK). The treatment is designed to stimulate meibomian gland activity, improve tear film stability, and reduce ocular surface inflammation. This protocol is unique compared to standard post-refractive surgery care because it targets cellular mitochondrial activity to enhance tissue repair and anti-inflammatory effects. It is non-pharmacological, non-contact, and well-tolerated, making it suitable for perioperative application. The light is delivered through closed eyelids, ensuring safety and comfort, and the device used is CE-marked for ophthalmic applications.

Participants in the Control group underwent the same procedural setup as the LLLT group, using the Eye-light® device (Espansione Marketing S.p.A., Italy). Instead of delivering therapeutic light energy, the device operated in demo mode, emitting less than 30% of the full treatment power. This configuration mimicked the visual and sensory aspects of a low-level light therapy session without producing biologically effective photobiomodulation. Sham treatment consisted of two 15-minute sessions, one 7 days before and one 7 days after Femto-LASIK. This design ensured masking of participants and investigators while preventing active therapeutic exposure in the control group.