Blepharitis and Meibomian Gland Disease (MGD) are essentially the same. MGD is the up to date medical term replacing the old term of blepharitis. MGD refers to a disease of the meibomian glands which results in a disfunction of oil. In order to understand the underlying disease we need to firstly understand the normal function of the meibomian glands.
What is the function of the normal, healthy meibomian gland?
The meibomian glands produce the oil layer of tears. Tears are made up of three layers:
- The inner mucus layer
- The middle water layer
- The outer oil layer
The oil layer is responsible for maintaining the stability of the tears and preventing the evaporation of the water layer.
What happens when the meibomian glands stop working properly?
In order to maintain the tears in a healthy environment, the meibomian glands produce a good quality oil which comes out of the glands when you blink. In diseased eyes there is a wide spectrum of abnormalities that can occur. The glands can:
- Produce poor quality oil
- Produce cloudy and infected oils
- Become blocked and not produce any oil at all
When the oil layer is poor in quality or reduces in thickness a cycle of progressive changes can occur which include:
- Increase in evaporation of the water layer
- Increased osmolarity (concentration) of the water layer which causes direct change to the cornea and conjunctiva
- Increased inflammation in the remaining tear film
All the above contribute to the ensuing dry eye, with symptoms which include burning, foreign body sensation, paradoxical watering, eye fatigue and blurring of vision.
How do I know if I have MGD?
If you have dryness, grittiness, scratchiness, soreness, irritation, burning, watering, eye fatigue then you could certainly be a MGD sufferer.
Are there any long-term consequences to MGD?
MGD is a progressive disease. As long as the glands are not producing oil they stagnate in the meibomian gland causing pressure. Eventually the glands give up working resulting in progressive atrophy (dying off of the glands) as well as truncations. That means that the glands slowly die away. However, treatment can be successful in slowing down or aborting the underlying disease.
What are the causes of MGD?
- Poor blinking associated with long-term computer use
- Contact lenses
- Most causes are simply unknown
What are the treatments for MGD?
The oil in the glands is usually partially or completely solidified and so this needs to be heated to allow it to melt. Once melted, pulsation and compression is required to express the oil. This is best done simultaneously so that the oils do not solidify in the interim once the heat is removed. The only system in the world that applies heat and peristaltic pressure at the same time is Lipiflow.
Only once the glands have had all the old oil expelled can the gland resume a more normal oil production.
Topical Heat Bags:
Whilst this form of treatment applies heat to the lid, there is no controlled expression of the glands. Even if one uses manual pressure the heat abates quickly by the blood flow in the lids. This treatment option is useful but does not provide concurrent pressure and heat at the same time.
Artificial Tears may be used to supplement the natural poor quality tears.
IPL is a heat system similar to topical heat bags, but once again does not provide simultaneous heat and peristaltic pressure expression of the glands.