As explained the tear film is spread by the eyelids helps to keep the eyes moist and removes debris. If any layer of the tear film is deficient symptoms of dry eyes will occur.

• Insufficient tear production.
• Tears are sufficient in volume but evaporate too quickly.
• Tears are sufficient in volume but of poor composition.

Evaporation of the tear film is by far the most common cause of dry eyes and some of the factors that cause evaporation include:

Many people experience temporary dry eye symptoms particularly due to the last three factors above. For most people symptoms are mild and won’t lead to long term problems although where symptoms are severe and left untreated dry eye syndrome can rarely lead to visual impairment and scarring of the eye surface.

Insufficient tear volume can be caused by a number of factors:

• Laser eye surgery – those who have corrective laser eye surgery often suffer from dry eye symptoms in the weeks after surgery but these often clear after a few months.
• Certain medications – antihistamines, beta-blockers, anti-depressants, both tricyclic and SSRI, isotretinoin and diuretics. These types of medication can sometime interfere with the production or disposal of tears. Beta blockers can sometimes affect the internal eye pressure. Please check with your pharmacist if customers taking medication are asking for advice or treatment for dry eye symptoms.
• Medical conditions – customers who suffer with dry eye often also have blepharitis (inflamed, scaly eyelids) or acne rosacea, whilst the risk of dry eye is increased by conditions such as Sjogren’s syndrome (autoimmune condition which attacks the glands that produce fluid leading to dryness of the eyes and other body organs), allergic conjunctivitis, contact dermatitis, rheumatoid arthritis, lupus, Bell’s palsy and HIV.

It should always be emphasised where the ability to produce tears is lost it cannot be regained so treatment will be lifelong.