Meibomian Gland Dysfunction

Meibomian gland dysfunction is a well recognised cause of dry eyes. Over {the} years, there has been a great deal of confusion regarding classification of this condition but recently, a detailed document has been produced that describes various aspects of this disease. This report was drafted by a panel of experts for {the} Tear, Film and Ocular Surface Society (TFOS) and provides a detailed guideline on classification and treatment of meibomian gland dysfunction.

It is an unfortunate fact that this condition is a rather under-recognised one. These new guidelines however have shed some interesting light on this condition. There are certain aspects of meibomian gland dysfunction that have an impact on {the} outcomes following anterior segment surgery. It is believed that {the} final result with regards to a patient’s vision depends primarily on {the} status of {the} film of tears from {the} eyeball. It is essential to have a good ocular surface in order for any surgery to be successful.

Another aspect that has been noticed with regards to surgical outcomes is {the} status of {the} tear film and its irregularities. This can cause inaccurate readings of {the} power of {the} eye which can in turn result in an error in prescription of intraocular lenses. In addition, patients who have meibomian gland dysfunction are at higher risk of developing infections and inflammation of {the} eye following cataract surgery.

Essential terminology Meibomian gland dysfunction

There are certain aspects of meibomian gland dysfunction that one needs to be aware of. These are closely related to {the} pathogenesis and pathophysiology of this condition. Below is a list of some of {the} commonly mentioned terms in {the} genesis of MGD.

  1. Blepharitis - this is a clinical condition that is characterised by inflammation of {the} entire eyelid. Inflammation that only involves {the} margin of {the} island is called marginal blepharitis.
  2. Anterior blepharitis refers to inflammation of {the} eyelid that lies in front of {the} gray line. Inflammation here can extend to {the} posterior eyelid margin.
  3. Posterior blepharitis refers to inflammation of {the} posterior aspect of {the} eyelid margin.
  4. Meibomian gland dysfunction is defined as a chronic abnormality that affects meibomian glands and one that is characterised by obstruction of {the} terminal ducts and an alteration in {the} secretion of {the} glands. In essence, it results in a destruction of {the} eyelid films and can make {the} eye rather dry.

The meibomian gland

The meibomian glands are specialised glands that are present at {the} removal of {the} eyelids. They are sebaceous glands that are responsible for {the} secretion of meibum, and oily substance that allows {the} tear film to stay on {the} eyeball and prevents it from getting evaporated. In addition, meibum prevents tears from pouring out of {the} eyeball onto {the} cheeks by forming a barrier between {the} eyelids and {the} eyeball.

The meibomian glands are located within {the} castle plates of {the} eyelids. Anatomically, there are around 50 glands in {the} upper eyelid and around 25 meibomian glands in {the} lower eyelids. The secretions from {the} meibomian glands are sebaceous and typically rich in lipids. Overall, research has shown that {the} meibomian gland secretions contain over 90 different kinds of proteins.

Pathogenesis of Meibomian gland dysfunction

Meibomian gland dysfunction results from reduced secretion of meibum from {the} meibomian glands or from excessive secretions as well. The former is called a low delivery state while {the} latter is called a high delivery state.

As is evident from {the} discussion above, meibomian glands are essential to keep {the} eyes healthy. Unfortunately, in {the} event that these glands become dysfunctional, {the} eyes can become dry. Furthermore, inflammation of {the} meibomian glands, frequently called meibomitis, can result in obstruction of {the} glands by its own secretions. This results in bacterial overgrowth, increased formation of free fatty acids, irritation of {the} eyes and {the} development of dry eyes and keratopathy.

Diagnosing eyelid problems of Meibomian gland dysfunction

There are certain ways through which meibomian gland dysfunction can be identified. A slit lamp examination or simple meibum analysis may possibly be sufficient. Once meibomian gland dysfunction has been detected, patients may possibly require some form of surgery once this has been controlled through medical measures.

Effect on quality of life related to Meibomian gland dysfunction

There is concern that MGD can affect a patient’s quality of life rather substantially. Patients can struggle to wear contact lenses and may possibly even find that their eyes look rather unsightly and puffy. This can have an impact on their personal and professional lives. 

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