Advertisement

What is dry eyes, and what causes dry eyes?

What is dry eyes, and what causes dry eyes?

Dry eyes (also dry eye syndrome) is an extremely common eye condition that can affect anyone although it is particularly common among postmenopausal women and the elderly in general.

Dry eye syndrome (DES) occurs when the eyes become ‘dry’ and uncomfortable as a result of an unstable and irregular tear film and ocular (eye) surface.

Its symptoms include feeling of ‘dryness’ on the eyes, gritty sensation (sandy feel, especially when blinking), burning sensation, itching, and redness of the eyes- all of which are likely to worsen over the course of the day.

Other symptoms are frothy discharge at the corner of the eyes, transient blurring of vision, and crusting of the eyelids.

Paradoxically, excessive tearing may also indicate dry eyes, and it happens as a form of reflex response to prolonged ocular irritation from dry eyes.
DES sometimes coexist with other eye conditions, like ocular allergies, and when it does the presenting symptoms are worsened.

The tear film

The front part of the eyeball is lined delicately with a layer of tears- called the tear film. This tear film is a complex fluid structure with as many as a hundred distinct constituents which are produced by a number of glands and groups of cells that line the eyelids.

It has three primary layers composed mainly of oil, water, and mucous, and these are evenly distributed over the ocular surface via the blink mechanism of the eyelids.

Some of the numerous functions of the tear film include provision of oxygen to the external parts of the eye; antimicrobial activities- preventing would-be infections of the external eye; flushing of debris, dust, and foreign bodies from the eye; and maintaining a smooth, regular optical surface (to help maintain a good visual acuity).

Perhaps it is this multipurpose nature of the tear film that makes its deficiency so worrisome.

What causes dry eyes?

Dry eye is classified into two basic types- aqueous deficient dry eye, where the eyes do not produce adequate tears, and evaporative dry eye, where the tears dry up too quickly.

Most individuals may have a considerable overlap of the two types. The main cause of dry eye syndrome is thought to be aging, as there is marked reduction in tear production as one ages. Other eye conditions (example, allergic conjunctivitis) and eye injuries can cause glands which secrete the various components of the tears to be impaired or damaged, disrupting the integrity of the tear film, hence causing dry eyes. Laser surgery, prolonged contact lens wear, and long-term use of some eye drops and systemic medications (including some blood pressure medications) may also cause and/or worsen dry eye syndrome.

Other complex systemic disorders (such as Sjogren Syndrome, and rheumatoid arthritis) and hormonal changes during pregnancy are strongly associated with dry eyes syndrome.

Behavioural and environmental factors such as reduced blink rate (especially during use of smartphones/computers and when reading books) as well as increased exposure to air-conditioned, dry, drafty, and dusty environment have also been identified as significant contributing factors to dry eye disease.

How is it detected and managed?

Your eye care professional (optometrist/ophthalmologist) after noting your presenting complaints and symptoms, will do an examination (of the eyes and other associated structures) to check for signs of the condition. He/she may also perform other investigative tests to detect some associated disorders, if necessary. Management of DES is primarily directed at controlling the symptoms of the disease, promoting comfort in the individual and prevention of ocular surface damage and other serious complications. Treatment options are mostly defined by the severity of the condition.

Management of the condition is primarily through prescribed eye drops, eye ointment and eye gels, which act as tear supplements and eye lubricants to help keep the eye (ocular) surface moist, smooth and regular. Your eye doctor may also prescribe an eyelid therapy, which includes eyelid warm compresses, eyelid hygiene, or taping of eyelids during sleep (in people whose eyes lag open during their sleep- called lagophthalmos).
‘Protective’ spectacles may also be prescribed to ‘shield’ the eyes and promote comfort in individuals who routinely use computer screens and other forms of display units for long hours.

Lifestyle reviews such as frequent blinking during reading, smartphone use, and television viewing are also necessary in controlling the symptoms of dry eyes. Computer screens and televisions should always be positioned below eye level in order to reduce the area of the exposed eye, and in turn reduce the incidence of dry eyes.

AC vents should as much as possible be directed away from the eyes, and avoid sitting in strong air-conditioned rooms or under strong-blowing fans for extended periods, as these are significant causes of dry eyes.
Adequate water intake, as well as intake of foods rich in Omega-3 fatty acids (example, salmon, mackerel, oysters) have also been shown to improve symptoms of DES, because they improve the quantity and the overall quality of tears produced by the eyes.

For individuals with very severe dry eye disease, your eye doctor may recommend a procedure that blocks certain ducts in the eyelids so tears produced by the eyes can stay a little longer on the eyes and in turn reduce the symptoms and promote comfort.

Dry eye syndrome in itself does not cause a direct loss of sight, but it can be a significant source of ocular discomfort and irritation which may affect one’s overall visual performance and wellbeing.

However, moderate to severe cases of DES, if left untreated, often lead to ocular surface exposure and severe complications such as conjunctivitis, cornea abrasion, cornea ulceration, and cornea scarring- which results in varying degree of visual impairment/ blindness.
Dry eyes can be effectively managed when diagnosed early and without complications-- see your eye care provider today for a better sight tomorrow.

Dr Felix Amoah, Resident Optometrist, Robert & Sons Ltd, Optical Service

Connect With Us : 0242202447 | 0551484843 | 0266361755 | 059 199 7513 |