Dry eyes occur when there are insufficient tears to adequately lubricate the surface of the eye. There are two main types of tears: basal (normal) tears which are always present, and reflex tears which are produced when crying or when the eye waters in the wind.
Symptoms of dry eye are experienced when the volume of basal tears are insufficient to keep the eye surface covered between blinks. Common symptoms include burning, stinging, grittiness or foreign body sensation, sore or tired eyes, and red eyes. Dry eyes often lead to vision that is blurry or filmy, and headaches and sensitivity to glare may be experienced. Occasionally the eyes may also water when outdoors in the wind if the surface is dry as reflex tears are produced in an effort to keep the surface wet.
These symptoms can also be worsened by environmental factors, where there is air movement, such as air conditioning at work and in the car, as well as the wind when outdoors. Often when concentrating, for example with computer use, television, reading and driving, a persons blink rate may also decrease which can also make things worse as the tear film breaks up before it is refreshed with a new blink.
Many of these symptoms and factors make sense when you consider that the eye needs a good tear film to be an ideal smooth optical surface. When the tear film does not provide continuous coverage of the eye, this can lead to the discomfort symptoms as the cells on the front of the eye must be kept wet to function properly. When this occurs vision may be blurry as the optical surface is no longer smooth and the same effect is gained by looking through scratched glasses. This is also similar to the dirty windscreen on the car: just as it makes the driver more sensitive to glare, the eye can be the same as the windscreen washer tears are not cleaning the eye surface properly.
Dry eye occurs more commonly with age, in women, and with certain medications and medical conditions. There are a number of things that can be done about improving the situation with dry eye.
The first involves the use of artificial tears, which aim to replenish and soothe the surface of the eye, and can be purchased without prescription. Artificial tears are special salt solution, to balance with the eye, with varying amounts of thickener to lengthen their effectiveness. The use of red eye drops is not recommended on an on-going basis as they only treat the symptoms and not the cause of the problem. We can recommend the most appropriate for you to use.
The second is to look to minimize the environmental factors that worsen dry eye. Consider changing or moving the desk at work away from air-conditioning ducts, and adjusting the vents in the car away from the eyes to point down. Have regular breaks when reading or using the computer and look to minimize glare sources when on the computer also. Conscious blinking may help but is difficult to sustain as it is normally an unconscious activity.
Finally, the use of sunglasses is recommended to cut glare and slow down the wind from drying the eye surface when outdoors. We recommend polarised sunglasses for this purpose and a close fitting pair will be best.