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MGD THERAPY - Overview

 

 

Meibomian Gland Dysfunction (MGD) is COMPLEX ... and offers DIFFERENT THERAPY OPTIONS

MGD is a complex multi-factorial pathologic condition that manly leads to a low delivery of functional Meibomian Oil onto the lid margin and consecutively onto the tear film with a consequent Tear Film Oil Deficiency that leads to itsINstabililty and evaporative Dry Eye Disease. This is the most frequent type of Dry Eye Disease - Lipid Deficiency due to MGD is thus the main causative factor for Dry Eye Disease.

According to the presently available scientific evidence, low delivery MGD is based on an obstructive process in the terminal ductal system that appears based on the two main pathogenetic factors of Hyper-Keratinization of the epithelium of the gland ducts and probably lid margin together with an increased viscosity of the lipids. that block, together or alone, the outflow of secretum from the glands.

The development, onset, and progression of MGD are influenced by internal and external factors that generally apply to dry eye disease as MGD presently appears as it main reasons. Age, levels of sex hormones and systemic disease as well as its therapy are main internal influence factors. A desiccating environment, low blinking frequency, contact lens wear and inflammatory eye disease are the main external factors.

 

THERAPEUTICAL TARGETS in MGD

Events that occur in MGD as CAUSATIVE FACTORS

  • HYPER-KERATINIZATION of the Epithelium due to events that are not yet fully understood but may include
    • SUB-CLINICAL INFLAMMATION due to
      • accumulation of BACTERIA on the lid margin and inside the glands and
        • their produced direct mediators (ENZYMES: lipases and esterases)
      • Modification of LIPIDS into irritant lipid species and downstream induced
        • production of soluble lipid derive inflammatory mediators (eicosanoid)
        • cellular cytokines of bystander cells
        •  
  • Modification of LIPIDS into species with INCREASED MELTING POINT
    • and consequently INCREASED VISCOSITY at normal Lid Temperature
  • increased PRESSURE inside the Glands when the obstruction already exists

 

Effects/ CONSEQUENCES that occur downstream of obstructive MGD are

  • LIPID DEFICIENCY on the Lid Margin and Tear Film

  • STASIS of Secretum inside the gland
    • with increased PRESSURE inside the Glands when the obstruction already exists
      • with downstream ATROPHIC Tissue Destruction
    • with secondary increasing BACTERIAL COLONIZATION