Dry Eye //
Tears play a vital role in maintaining corneal smoothness and clarity. They provide lubrication, nutrition and protection for the outer surface of the cornea. Tears are produced in the lacrimal gland which is located beneath the upper, outer, bony rim of the orbit. From there they are distributed by gravity and blinking over the conjunctival and corneal surfaces. Tear loss occurs primarily via drainage through two narrow channels in the inner corner of each eye (actually the lid margin, medially) that connect to the nose and by evaporation.
Mild reductions in tear production are frequently asymptomatic. With more significant declines, the corneal surface may become dry, rough and irritated. Symptoms such as burning, itching, foreign body sensation and blurred vision are frequently present. Exposure to wind, heavy air conditioning and antihistamines are factors that often aggravate the problem. A dry eye problem may be associated with other, non-ocular conditions such as a dry mouth, Sjogren’s syndrome or rheumatoid arthritis.
Dry eyes cannot be cured, but symptoms can usually be controlled and serious complications prevented. Treatment consists primarily of the instillation of various “artificial” tear drops. Artificial tears may be applied sporadically, or as often as every thirty minutes. The frequency of instillation as well as the viscosity (thickness) of ocular lubricants depends on the severity of symptoms and the extent to which the corneal surface is involved. Thicker lubricating ointments may also be used. Ointments have the advantage of a longer duration of action since they do not evaporate or drain through the tear drainage channels as rapidly as artificial tears. Their principal disadvantage is that they temporarily blur vision because of their greater thickness. Many patients prefer to use ointments only at bedtime because of this. The appreciation that low level inflammation may be a cause of a dry eye has led to the use of topical anti-inflammatory steroids and immune system suppressants (immunmodulators) in the treatment of selected dry eye patients.
A variety of other approaches including the use of omega 3/6 fatty acids orally and blood serum derived tears may also be considered. Special glasses or goggles are recommended to help decrease evaporation of tears from the corneal surface when evaporative tear loss is a significant issue. Minor surgical procedures that involve the insertion of temporary drainage channel plugs or more permanent channel closure with cautery (heat) to reduce tear loss are considered in severe dry eye patients.
The chronic character of dry eyes and the absence of a cure are frequent sources of frustration. You should be reassured that most patients’ symptoms can eventually be controlled with treatment and serious complications, including loss of vision, prevented.