The feeling of a dry and irritable eye, although common is not always caused by a lack of tears. The lack of tears is seen in very uncommon conditions such as Sjogren’s syndrome, chronic conjunctivitis and after radiotherapy to the head.
The most common cause of the feeling of dryness is an imbalance in the composition of tears occasionally also related to poor movement of the eyelids.
The human tear is a remarkable fluid. It must protect the surface of the eye from dryness, flush dust, allergens and other debris from the surface of the eye and provide protection from all types of germs.
Tears consist of mucus, oil and a complex, salty water. Because the surface of the eye is greasy in nature, water will not stick well to it. This is where the mucus of the eye is important. Mucus acts like a detergent allowing the watery tear to stick to the surface and to protect it from dryness. Each time we blink, the upper eyelid comes down to meet the lower lid where the tear reservoir is stored. When the upper lid lifts, it brings with it a thin sheet of tear to coat and protect the eye.
This “tear film” must remain intact until the next blink. This may be anywhere from a few seconds to a half a minute or more. If the tear film begins to “break up” before the next blink rejuvenates the tear film, dry spots will begin to form and eventually the symptom of dry, irritable eye will be apparent. Thus, it is now evident that the dry eye feeling can occur with tears present, simply because the tear film is not stable long enough to protect from blink to blink. Unfortunately, we cannot be thinking of blinking all the time, as this is an unconscious and automatic event.
In health, the tear film protects from dryness up to extremes of environmental stress. However, even the perfect tear film may not cope with extremes of dryness and dusty air. Under such circumstances, even a normal eye may feel tired, irritable and dry.
If any part of the tear composition is reduced in quality or if the lids do not function properly, symptoms will occur. Classically, that of an irritable dry feeling eye with foreign body sensation, worse as the day advances especially if the person tries to read, watch TV use a computer or encounters a dry, dusty, windy or smoky environment.
It is more usual for some degree of failure of several parts of the tear film than solely from failure of one part alone.
After examining the eyelid and tear film, the eye specialist will have a good idea where the problem lies. Not always is it possible to achieve improvement, however, if you wish to feel more comfortable, you must be absolutely compliant with the following treatment for at least two months. If at the end of this time, you feel no improvement in symptoms, you may wish to reappoint to the eye specialist to determine if further treatment is available. There is no point in further assessment if you have not been compliant with treatment as the doctor will not be able to help further.
TYPES OF THERAPY
These should be applied not less than three times a day, preferably five times a day in each eye, one to two drops at a time. Available over the counter (prescription not required) the following are suggested:
Refresh Tears Plus /10
Poly Tears /10
I suggest trying these sequentially and score each at the end of bottle use, scoring each out of ten. Continue using the one which provided the greatest comfort.
Preservative Free Eyedrops
These are more expensive but worth trying if the previous drops sting or do not help. Use with similar frequency as described above, or as directed by the manufacturer.
Thera Tears /10
Bion Tears /10
I suggest trying these sequentially and score each at the end of the box use, scoring each out of ten. Continue using the one which provided the greatest comfort.
Not infrequently the eye suffers dryness because of rapid evaporation with tears or because the tear film is not smooth. This is nearly always consequent to dysfunction of the oil film which originates from the eyelid margins. The most frequent cause is blepharitis, a very common condition, but occasionally occurs even without identifiable disease. To promote improved oil flow, the following should be adhered to:
Warm Lid Compress
Using a clean face washer or face flannel, place in warm to hot water and then squeeze out excess and fold several times. As shown in picture, place on lids and apply moderate pressure to lids usually, 30 seconds per eyelid, reheating cloth with each application.
Using a cotton bud, dipped in cool boiled water, wipe along the lid to clean eyelashes and the lid margin. (See photo).
Bathe with Bicarb soda solution. (The doctor will provide a separate information sheet)
This is prescribed for significant blepharitis, usually related to Rosacea of skin. Used for up to three and a half months each course. Stop if side effects of thrush or stomach upset occurs.
This is a new and novel treatment aimed to improve the stability of the tear film. This is a spray rather than a drop and should be used as recommended on the packet.