“Meibomian gland dysfunction has been identified as the main cause of dry eye syndrome around the world”. These are the words from the first World Congress report about meibomian gland dysfunction (MGD) organised in 2010 by ARVO (Association for Research in Vision and Ophtalomogy). More than 50 members from the most renowned ophthalmology and optometry experts around the globe gathered for this congress.
Dry eye syndrome is a common condition affecting between 5 to 15% of the population – with regional variations – with symptoms increasing with age. Modern lifestyle factors (such as working on computers screens, driving cars, artificial lights, air pollution and contact lenses) make dry eye syndrome even more of a nuisance and a more regular occurrence.
Generally speaking, dry eye conditions are the result of a lacrymal layer issue, either caused by insufficient tear production or excessive evaporation of tears (evaporative form).
These days it’s widely agreed that a large majority of cases (80%) are caused by the evaporation form, mainly due to the absence or insufficiency of the external lipid layer of the lacrymal film secreted by the meibomian glands. There are around 80 meibomian cells located on the upper and lower eyelids.
These cells produce a fatty substance that prevents tear evaporation, adapts to irregularities of the eye surface and ensures a perfectly convex dioptre.
Lipids are made up of polarised fatty acids, whose fluidity is determined by body temperature. Non-polarised on the surface, they provide stability of the lachrymal fluid and enable lubrification of the palpebral conjunctiva. The contraction of the ciliary muscle, allows the lachrymal film to spread out.