Dry Eye

• Dry Eye


  Condition where insufficient tears are produced to lubricate and nourish the eye. People with this condition either don't produce enough tears or have a poor quality of tears; it's a frequent source of eye irritation that causes varying degrees of discomfort. It's a chronic condition, with no cure, and it's common, particularly in older adults.
• Exact prevalence of dry eye is unknown but it's common
• Almost 3% of older adults will develop dry eye each year and its prevalence increases with increasing age
• Dry eye is more common in women than men
• Aetiology of dry eye

  Tear film instability brought on by environmental and patient factors that leads to a loss of homeostasis of the tear film. This instability increases electrolyte concentrations, resulting in dry eye.
• Medications that can exacerbate or produce side effects of dry eyes

  • Diuretics
  • Isotretinoin
  • Hormone replacement therapy, particularly oestrogen
  • Androgen antagonists
  • Cardiac arrhythmic drugs
  • Beta blockers
  • Selective serotonin reuptake inhibitors (SSRIs)
  • Drugs that have an anticholinergic effect e.g. tricyclic antidepressants, antihistamines
• Symptoms of dry eye

  Eyes that burn, feel tired, itchy, irritated or gritty, with symptoms worsening throughout the day. The conjunctiva isn't red unless irritated (e.g. eye rubbing or allergy). Irritation and burning is caused by decreased tear production. The symptoms can fluctuate in intensity and are intermittent, with symptom severity not always correlating with clinical signs.
• Questions to ask to indicate dry eye syndrome


  Have you had daily, persistent, troublesome dry eyes for more than 3 months? Do you have a recurrent sensation of sand or gravel in the eyes?
• Aggravating factors for dry eyes

  • Dry air
  • Wind
  • Dust
  • Smoke
• Normally no other symptoms are present in dry eye. If the patient complains of a dry mouth, check for medication causes. If medication is not implicated, then symptoms could be due to an autoimmune disease.
• Ectropion


  When the lower eyelid turns outward, overexposing the conjunctiva to the atmosphere and leading to eye dryness
• Differential diagnosis for dry eye

  • Dry eye syndrome
  • Blepharitis
  • Sjogren syndrome
  • Medicine-induced dry eye
  • Ectropion
  • Rosacea
  • Bell's palsy
• When to refer for dry eye

  Associated dryness of mouth and other mucous membranes - could be Sjogren's syndrome. Outward turning lower eyelid - requires medical intervention as it could be ectropion. If a child has dry eye - dry eye in children is rare.
• Treatments for dry eye

  • Artificial tears (e.g. hypromellose, carmellose, carbomer, sodium hyaluronate)
  • Lubricating ointments (e.g. wool fats)
  • Polyvinyl alcohol eye drops
• Artificial tears


  May require hourly or even half-hourly dosing initially, which should reduce as symptoms improve. Transient stinging and/or burning may be reported.
• Carbomer eye drops


  Manufacturers recommend that adults and older adults use one drop three or four times a day or as required, depending on patient need. Due to the products' viscosity properties, carbomer should be used last if other eye drops need to be instilled. Manufacturers advise avoidance in pregnancy and lactation due to insufficient data, but clinical experience has shown they can be used safely in these patient groups. Blurred vision after instillation.
• Lubricating ointments


  Useful at bedtime when prolonged lubrication is needed, but because they blur vision, they are unsuitable for use during the day.
• Polyvinyl alcohol eye drops

  Blurred vision after instillation.
• Many eye drops contain benzalkonium chloride, which by itself can cause eye irritation. If symptoms persist, or are worsened by the eye drops, it may be worth trying a preservative-free formulation or single-dose unit preparations.