General EYE ADVICE

Dry Eye

As age increases the quality and the quantity of the tears also decrease, leading to symptoms of dry eye. Good quality tears contain various chemical constituents in good proportion. These include optimal amounts of aqueous (watery), mucous and lipid-type substances. In some people such as menopausal women, there are decreased amounts of mucous in the tears, hence they become less viscous and do not stay on the surface of the eye as well. In other people such as those suffering from rheumatoid arthritis, there is decreased production of the aqueous component of the tears, leading to true dryness of the eyes. Intensive close work, such as computer use, is often associated with decreased or incomplete blinking and consequent drying of the eyes.

The problem of dryness of the eyes is often interrelated with chronic inflammation of the conjunctiva (the translucent membrane covering the tough white coat of the eye). Over a longer period of time, chronic inflammation from allergic or infective conjunctivitis can both adversely affect the quality and quantity of the ongoing (basal) tear secretion of the eyes. Conversely, inadequacy of tears allows for a greater degree of inflammation in infective or allergic conjunctivitis. The symptoms of eye irritation are compounded when there is a true concurrence of both a chronic inflammatory condition and dry eyes. A further possible compounding factor is inflammation of the lipid glands of the lids (meibomianitis). External eye inflammation is an important contributing factor to meibomianitis, which can also exacerbate the symptoms of dry eye due to excess lipid secretion into the tears.

Probably the most common contributing factor of eye irritation is chronic infection spreading from adjacent nasal/sinus areas. The symptoms of eye irritation in chronic conjunctivitis are made worse by inadequate tears. This is primarily because the eye cannot clear away the infection as well as it normally can when there are adequate tears. However, treatment for the dry eye problem alone in this case will not eliminate those symptoms related to infection. Treatment should be primarily directed towards eliminating the cause of chronic infective conjunctivitis. In general, as treatment for dry eye is often long-term, it would more efficacious to first attend to any other causes of external eye inflammation and then re-assess the symptoms to see if, and to what extent, any dry eye treatment is necessary

The types of symptoms in "dry eye" depend on the causes and associated pathology of the external surface of the eye. They range from stinging and burning of the eyes, to a feeling as if there is grit in the eyes or a very dry feeling as if there is paper wrapped around the eyes.

 There are various treatments for those symptoms that are truly caused by an inadequacy in the tears and not by other compounding inflammation. The simplest but more ongoing measure, is the regular installation of lubricants. These are available in the form of drops, ointments or gel (semi liquid). As some people are sensitive to preservatives the best option is to use single dose vials of eye drops or preservatives free ointments. The eye drops come in a range of viscosity's and given the availability of gels an ointments, the practitioner now has a range of eye lubricants which can be employed depending on the individual's needs.

If dryness of the eyes is aggravated after prolonged viewing such as with VDU work, this may be due to a reduced rate of blinking or incomplete blinking. One should aim to blink fully at least twelve times per minute. If there is a dry eye problem, the rate of blinking may have to be doubled to prevent symptoms. Various other treatments are available for dry eye such as punctal occlusion and increasing the humidity of the environment e.g. wearing air tight goggles, employing a humidifier at home and avoiding air-conditioning etc.  

Next