Multiple Cause Diagrams (MCDs) can be used to find solutions to systemic problems. This diagram tries to explore treatment options that could theoretically be available to a person who has been diagnosed with a particular type of blepharitis (inflammation of eye lids). This type of blepharitis often leads to 'pink eye' and  'dry eye syndrome'. It  is caused by rosacea of the eye lids, a systemic disease which can only be controlled but not cured.  The MCD also assumes that the patient's tear glands do not produce enough tears, which  further complicates his eye condition.  The broken green lines indicate treatment options.Their aim is to weaken or disrupt links that keep the malignant process going.

Ophthalmologist Craig Blackwell described the 'Dry Eye Cycle' in two excellent videos with graphic descriptions. From his description it becomes clear that the Dry Eye Cycle really consist of two self-reinforcing feedback loops. I have constructed these feedback loops here because they help explain the cycle, and understanding it may be very useful for suffers of the often debilitating 'dry eye syndrome '. The process usually starts with one of two deficiencies: the oil secreted from oil glands is too thick and does not adequately cover the aqueous film leading to evaporation and dryness or tear glands do not produce enough tears.  Dr. Blackwell stresses the role of inflammation which can lead to the progressive worsening of the condition and  which should be controlled. He suggests various treatments. I highly recommend watching the videos

https://www.youtube.com/watch?v=ooYcjzNtn58

https://www.youtube.com/watch?v=TwpWKCM31JI