Dry eye can be caused by any factor which interferes with the normal functioning of the tear film. For example:

• Ageing is associated with abnormal lipid production, which can give rise to evaporative dry eye(i.e. when the tears evaporate too quickly). 2 - 3 times more women than men are affected.
  
  

• Climate - air conditioning, central heating, air travel, pollution, wind, heat, sun exposure and high altitudes can all make the eyes dry.
  
  

• Systemic Disease conditions in which dry eye occurs include rheumatoid arthritis, Parkinson’s disease, diabetes and auto-immune diseases.
  
  

• Eye Diseases affecting the meibomian glands and eyelid conditions contribute to tear film instability and cause dry eye.
  
  

• Medications the side effects of many therapeutic treatments, for example, antihistamines, HRT and some sleeping pills can make the eye dry.
  
  

• Low blink rate activities such as reading, computer use, watching television can make the eye feel dry.
  
  

• Contact lens wear physically interferes with the tear film and rubs against the conjunctiva under the eyelids.
  
  

• Eye surgery particularly refractive correction.