Outcomes Of Low- Level Light Therapy Before And After Refractive Surgery For The Prophylaxis Of Postoperative Dry Eye

Although refractive surgery is widely recognized as one of the safest and most effective procedures in modern medicine, the risk of iatrogenic dry eye disease (DED) should be considered and, hopefully, addressed. This study aims at assessing the effects of low-level light therapy (LLLT), also known as photobiomodulation, on ocular surface parameters in patients undergoing refractive surgery. 

Prospective, randomized, masked, controlled study

Patients scheduled for photorefractive keratectomy (PRK) or femtosecond-assisted laser in situ keratomileusis (femto-LASIK) were randomized 1:1 to receive LLLT (group 1) or sham treatment (group 2) using the EYE-LIGHT device (Espansione Group S.p.A., Bologna, Italy). The LLLT session lasted 15 min and was performed at 2 time points: 7±2 days before (T0) and 7±2 days after surgery (T1). Ocular surface workup included non-invasive tear break-up time (NIBUT), interferometry, tear meniscus height (TMH), meibomian gland dropout in both superior and inferior eyelid, Schirmer test and ocular discomfort symptom evaluation, and was conducted at T0 and T1 (before each mask session), T2 (30±3 days after surgery), and T3 (90±5 days after surgery).

Out of 57 enrolled patients, 43 (mean age 38±11 years, 61% male) completed the study. In group 1, no significant differences were observed for all parameters across the different time points. Conversely, group 2 exhibited a significant decline in TMH (from 0.26±0.07 at T0 to 0.21±0.04 mm at T4, p<0.001). Ocular discomfort symptoms showed no statistically significant differences after treatment in both groups.

LLLT is a non-invasive treatment that stabilizes ocular surface status during the journey of patients undergoing refractive surgery preventing the decline of tear production registered in non-treated patients.