Abstract
Purpose:
Meibomian gland dysfunction (MGD) results in a depleted or dysfunctional tear lipid layer and increased evaporation rate of the underlying aqueous. Improvements in lipid grade (LG) and non-invasive break up time (NIBUT) have been demonstrated in MGD following a short course (3 sessions) of intense pulsed light (IPL) therapy (E>Eye, E-Swin, France), however, evidence with regard to selecting the optimal treatment regime is lacking.
Methods:
A cohort of 28 participants (68% female and aged 23 to 73 years) with signs and symptoms of MGD, undertook 3 IPL sessions over a 45-day period as part of a randomized, double-masked, placebo-controlled trial. Instantaneous treatment effects (ITEs), defined as the changes in LG and NIBUT immediately after IPL treatment, were calculated and their magnitudes compared over 3 time points; 2 and 6 weeks following initial treatment.
Results:
NIBUT improvement after treatment was significant (ANOVA F(2,54)=6.42, p=0.003) only after the third IPL session. While still positive, the treatment effect was not significantly different between the first and second sessions (p=0.977). Similarly, treatment resulted in a median LG ITE of two grades (where 0=absent, 5=maximal), to level 5 by the third treatment (p<0.001). Again, such differences were not apparent at the first two treatments. The increase in LG over the three sessions was highly correlated with the increase in NIBUT (PLUM,R2=0.945,p<0.001).
Conclusions:
In the absence of supplementary warming or gland expression, IPL therapy effected cumulative increases in absolute lipid grade and tear film stability that were statistically and clinically significant after three treatments. Moreover, a more substantial instantaneous treatment effect was evident by the third treatment, providing supportive evidence of the ability of IPL therapy to improve gland function. Current findings support deferring clinical judgment of IPL benefit in MGD until at least the third IPL session, and suggest including at least three sessions in future research studies evaluating optimal treatment strategies.