Intense Pulsed Light for the Treatment of Evaporative Dry Eye

Abstract

Background Meibomian gland dysfunction (MGD) is a major aetiological factor in the development of evaporative dry eye (EDE), a common presentation in ophthalmic clinics which causes significant detrimental effects on quality of life. Traditional management strategies often fail to provide sustainable solutions, prompting patients and clinicians to seek alternative options. One novel treatment to emerge in recent years is intense pulsed light (IPL). Several, largely retrospective or open-label, studies have demonstrated an improvement in the signs and symptoms of EDE after periocular application, but possible mechanism(s) of action of IPL in the context of long-term MGD management remain poorly understood. Purpose To explore the dry eye practices of New Zealand eyecare professionals against current evidencebased guidelines, then utilise contemporary diagnostic metrics to evaluate the therapeutic potential of periocular IPL application as a treatment for MGD and the potential mechanism(s) of action. Methods Eighty-seven subjects with mild to moderate MGD were enrolled in a prospective, randomised, double-masked, non-paired eye, placebo-controlled study. Participants randomised to receive a course of four IPL treatments or four sham treatments (control), were evaluated at baseline, prior to treatment on Day 15, Day 45, Day 75 and as a follow-up only on Day 105 using: 1) validated dry eye questionnaires, 2) clinical diagnostic techniques, 3) non-contact aesthesiometry, 4) RNA expression of neuroinflammatory biomarkers, 5) tear film lipidomics, 6) in vivo confocal microscopy and 7) lid margin microflora assessments. Results A total of 30 participants (70% female, mean ± SD age of 55 ± 14) were randomised to the placebo arm of the study, and 56 participants were randomised to the treatment arm with 4 IPL flashes (n = 28, 68% female, mean ± SD age of 48 ± 15) or 5 IPL flashes (n = 29, 62% female, mean ± SD age of 56 ± 17) applied to the inferior periocular zone. Following participation, dry eye symptom scores in the active treatment arms significantly improved from baseline relative to placebo (Ocular Surface Disease Index score: 4 Flashes vs. Placebo, p = 0.04; 5 Flashes vs. Placebo, p = 0.03). Improvements in lid margin appearance and meibomian gland function also differed significantly between the groups. No changes to clinical and biomarkers of ocular surface neuroinflammation were observed, however IPL exerted mild modifications to the tear lipidome biochemistry. Conclusions IPL therapy was well tolerated and proved to be an effective management option for MGD. Cumulative improvements in EDE symptoms, tear film lipid layer thickness, meibomian gland capping and meibum expressibility may be related to alteration of tear lipid profile rather than reduction in ocular surface inflammation, thus broadening the current understanding on the possible mechanisms of action underlying IPL therapy for MGD relief.