“Dry eye syndrome” (also known as keratoconjunctivitis sicca) is a common cause of ocular hyperaemia and irritation due to the eye surface being inadequately lubricated. Although this condition can affect anyone it tends to occur with increasing age (up to 7% of people in their 50’s, increasing to around 15% of 70yr olds).
Causes of dry eyes include:
- Often there is no specific cause other than reduced tear production with increasing age, especially in females after the menopause
- Some medications can cause or exacerbate dry eyes eg diuretics , antidepressants, antihistamines, oral contraceptive pill
- Eyelid margin disease, especially posterior blepharitis, which results in inadequate lipid secretion from the meibomian gland orifices. Consequently there is increased tear evaporation from an unstable tear film (“evaporative dry eye”), which can be detected during slit lamp examination using fluorescein
- More rarely tear production can be significantly reduced by conditions directly affecting the lacrimal gland eg lymphoma, Sjogrens syndrome. A Schirmer’s test can be used to determine baseline tear production. Small strips of filter paper are placed into the lateral lower fornices and the degree of wetting is noted over a period of 5 minutes
Symptoms of dry eyes
Most commonly a bilateral condition, although one side may be worse:
- Poor wetting results in ocular surface irritation including red sore eyes, burning and /or gritty sensation. These symptoms tend to be more pronounced later in the day
- Intermittent blurring of vision due to inadequate corneal wetting, especially during periods of concentrated visual tasks (which reduce the blink rate) eg computer work, driving. Significant corneal involvement may result in photophobia and slit lamp examination using fluoresecein reveals “spotty” staining know as superficial punctate keratopathy (SPK)
Dry eye treatment options
The majority of patients have relatively mild dry eyes and just require artificial tears to supplement their inadequate tear film. There are several different types on the market including lubricating drops, gels and ointments. Many patients often benefit from the additional treatment of any associated posterior blepharitis (see "Blepharitis" section).
When drops are required more than 4-6 times a day it is usually desirable to use a preservative free product in order to reduce potential ocular surface toxicity (especially from benzalkonium chloride). In addition patients requiring frequent topical medications, especially those with a reduced Schirmer’s tear production, may benefit from reversible punctal occlusion to reduce tear drainage.