Dry Eyes Condition
Millions in the UK have tired, gritty sore or red eyes which affects their life.
Dry eyes are increasing amongst young adults due to our modern lifestyle.
The patient with dry eyes is, “looking at having as comfortable eyes as possible”.
Dry eyes have less than normal moisture on the eye surface, either caused by a lack of tears or by poor tear quality. Patients with contact lenses often experience dry eyes too due to less blinking. Cigarette smoke, air conditioning and a dry climate, all contribute to exposure to dry eyes by increasing tear evaporation resulting in dry eye symptoms. Failure to blink regularly, such as when staring at a computer, mobile phone or tablet screen for long periods of time or watching a film in the cinema, can also contribute to drying of the eyes. When we concentrate on a screen in front of us our blink rate reduces, is incomplete and tears evaporate. This is made worse if the tear quality is already poor. In fact there is a vicious circle as poor blink leads to poor meibomian gland flow and worsening of tear quality.
Usually, these mild dry eye symptoms do not reflect upon a serious condition and are easily rectified. Dry eyes are a common eye complaint, particularly in older adults as tear quality and production decreases with age, particularly in peri-menapausal and menopausal women.
Tears are necessary to lubricate and nourish the surface of the eye and wash away particles and foreign bodies. They are also needed for clear vision, as with each eyelid blink, tears are spread across the cornea, which nourishes and helps maintain corneal smoothness, keeping vision clear. A healthy tear film helps reduce the risk of eye infection and maintains comfortable eyes.
The symptoms of dry eyes
- A gritty, sand-like sensation
- Soreness or burning
- Contact lens wear difficult
- Tired eyes with computer screen use
- Difficulty in opening the eyelids in the mornings
- Mucous stickiness
- Paradoxical watering from reflex tears to compensate for the dryness
- Very dry eyes can damage vision
Tears are produced by glands in and around the eyelids. There is a large tear gland (the lacrimal gland) and several, smaller tear glands in the conjunctiva. Tear production reduces with age, with some medical conditions, or as a side effect of certain drugs. Tear production can cease in some scarring conjunctical disorders. Sunshine, wind and a dry climate all increase tear evaporation and hence reduce tear volume and hence eye surface wetness, giving symptoms of dry eyes.
The tear film on the surface of the cornea consists of three layers: oil, water, and mucus. Oil helps prevent the tears from evaporating, mucin helps spread the tears evenly over the surface. Each component serves a function in protecting and nourishing the front surface of the eye. If any of the three layers are affected, a dry eye is felt. The oily layer is often deficient with meibomian gland dysfunction, where the meibum is either too thick and the gland openings plugged, or not produced (atrophic).
Causes of dry eyes
- Dry eye is a part of the ageing process and is experienced to some extent by everyone over 65 years. Tear production reduces from the age of 40
- Hormonal changes in women, such as in pregnancy, oral contraceptive and with peri-menapause and menopause
- Dry climate or work environment
- Excessive computer screen use
- Blepharitis and Meibomian gland dysfunction is often associated with dry eye.
- Laser refractive eye surgery (e.g. LASIK, or LASEK)
- Medicines including antihistamines, decongestants, some blood pressure reducing medicines and antidepressants can reduce the quantity of tears
Less common causes:
- Rheumatoid arthritis with Keratoconjunctivitis sicca (KCS)
- Diabetes, thyroid disease and other autoimmune conditions are associated with dry eyes
- Sjogren’s disease is a specific type of dry eye where the eyes and mouth and other mucosal surfaces are dry
- Some patient’s eyelids are too open or have a reduced blink, such as with Thyroid Eye Disease and Facial Palsy
- Drug-induced ocular inflammations (e.g. Stevens-Johnson disease)
- Ocular pemphigoid, a rare but important cause of severe dry eyes
- Previous trachoma
Before the oculoplastic surgeon decides on whether the patient has dry eyes, they will take a thorough history, measure the vision and then examine the eyes. The oculoplastic surgeon will ask about eye symptoms and onset, general health, previous eye infections and conditions, contact lens wear, previous laser eye surgery, environmental factors and whether eyedrops used. Medical conditions, drugs taken, allergies. They will specifically look for blepharitis and meibomian gland dysfunction as dry eyes and blepharitis often co-exist.
A thorough eye examination is performed. The Schirmers test using a small strip of filter paper and measuring the extent of moisture absorption or Tear Osmolarity is measured before the eyelids are examined.
We examine the skin around the eyes, the eyelid position, blink rate, exclude plaque-like debris on the eyelid margins and look under the surface of the eyelids. Special dyes are instilled into the eyes to observe the tear film and cornea surface.
The lid margin and health of the meibomian glands are especially examined in order to determine if there is anterior blepharitis or meibomian gland dysfunction with an oily meibum deficiency. Possible Dermadex infection is looked for.
The degree of lid margin inflammation, granular deposits of meibum and skin cells, are assessed and whether there are posterior lid margin telangiectasia present indicative of ocular rosacea.
The cornea is examined with the bright light and magnification from the slit lamp. A blue light is used after administration of fluorescein drops to help see any dry spots on the eye and examine the tear break up time.