Effect of Eyelid Stimulation on the Tear Film in Meibomian Gland Dysfunction

Abstract

Abstract: : Purpose:Histologic analysis of human and rabbit models have shown that the muscle of Riolan surrounds the ductules of the mebomian glands in the tarsal plate and could possibly aid in the expression of meibum. A study involving the stimulation of eyelid muscles with a transcutaneous electric nerve stimulator unit in a rabbit model showed secretions percolating from the meibomian gland orifices. The purpose of the present study is to stimulate the muscle of Riolan to aid in meibum expression in patients with meibomain gland dysfunction (MGD). Methods: Twenty patients with symptoms of ocular irritation and an age and sex matched control group. MGD in this study is defined as the presence of significant orifice plugging (> 5 orifice); cloudy, turbid or inspissated secretion; and reduced volume of secretion on digital pressure on the lids. Tear lipid layer thickness, tear break-up time, evaporation rate and lid margin lipid level will be assessed after unilateral eyelid muscle stimulation using a transcutaneous electric nerve stimulation (TENS) device while contralateral eye of subject will be used as control. Quantatative symptom scoring for ocular irritation will be used to evaluate patient response to treatment. The primary analysis of efficacy is based on mean changes of primary outcome measurements from baseline to the 2 week follow up. Ordinal categorical variables will be analyzed with the Wilcoxon-rank-sum test to compare the changes between treated and control eyes. Results: Initial pilot data demonstrate bubbles percolating from the meibomian gland orifices during stimulation of the eyelids in 50% of patients tested. An improved lipid layer appearance of the tear film (ie.oblique and vertical to more horizontal interference patterns) , an increase in tear break-up time and lid margin lipid layer (meibometry) were observed. Five patients after 1 week of treatment reported marked improvement in symptoms from moderate to severe to mild to trace (2 fold improvement). Conclusions: Preliminary result shows that stimulation of eyelid muscles is effective in expressing secretions from the meibomian gland and could be used as an adjunct to the treatment of chronic blepharitis. Symptoms can be alleviated due to the stabilization of the tear film by increasing the lipid layer and retarding the evaporation rate of the ocular surface.

Keywords: eyelid • lipids • cornea: tears/tear film/dry eye