Patients often complain of many symptoms that may represent more then one condition. One of the most common difficult differentiations to make is whether it is an allergy or dry eyes.

The symptoms of both disorders are similar and often over lap. They both cause red eyes, may create a burning sensation and both can itch even though we were all taught that only allergies make the eye itch. Tearing and mild discharge are common and frequently the patient will have all of these symptoms and if a poor historian may confuse when, where and how often they suffer. They are however, very different conditions and treatment will only be affective if appropriate for the anomaly.

Each condition has specific pathophysiology. Dry eyes are caused by tear film insufficiency, instability or a poor mixture of the required tear components. If there are glandular irregularities such as Meibomianitis the lipid layer will suffer. This will result in more rapid tear film evaporation. Goblet cells produce Mucin whose function is to bind the tears to the epithelium layer of the cornea. Insufficient quantities of Mucin will result in the tears running of the eye too rapidly. Lacrimal glands produce Aqueous, the water part of the tears. Water represents most of the tears and an insufficient amount obviously has a dramatic affect on the volume of tears. The most accurate method of measuring the aqueous volume is with Fluorophotometry. Blinking mixes all these components up and spreads them out over the cornea. Normal blink rate is once every 5-6 seconds. However, if one stares at a computer that rate will decrease to 10-12 seconds drying the eyes out. Therefore, when someone has dry eyes, forcing a correct blink rate is crucial to successful treatment.

The etiology or cause of dry eyes is also quite varied. Eyes tend to decrease tear production with age or hormonal changes, certain diseases and treatments like for cancer or surgeries such as LASIK. Blepharitis ( lid inflammation) and contact lens wear are also common causes of dry eye.

The pathophysiology of Ocular allergies is quite different. Exposure of a sensitive individual to an allergen will result in the release of antibodies that bind to Mast cells. The mast cells then release histamine that cause the full allergic reaction. The result is itchy, puffy eyes, swollen lids, tearing and discomfort.

Unlike dry eyes, if an individual is not sensitive to an allergen then there will NEVER be a reaction. The key to appropriate treatment is making the correct diagnosis.

Treatment for dry eyes begin with artificial tears several times per day. If that does not help then going after the source is required. New theories include an allergic reaction in the tear producing mechanism and thus prescribing a mild steroid like Lotemax 3 times per day in conjunction with the artificial tears is done. If that still is not adequate, then Restasis which is a reformulation of an old drug Cyclosporin is employed. Cyclosporin is an anti autoimmune drug that has found a new use. Care must be employed when using this medication because any infection that occurs while taking it may be much worse. Therefore, patients must be counseled to stop using it if any disease occurs. Finally, punctal plugs can be inserted to keep tears in the eyes in addition to these treatments. Wet cell eye glasses that trap moisture are not often used, but can be employed as a last resort as well.

Allergy treatment is much simpler. Eye drops that are Antihistamine/Mast cell inhibitors are the best. They attack the source and symptoms of the disease. Comfort is fast and long lasting. The number 1 drug of choice these days is either Pataday or Patanol. I have found that similar drops like Elestat, Optivar and the OTC drops are not as effective. If these medications are not enough to alleviate the condition, then steroid eye drops will do the trick. We start with Lotemax and graduate to the stronger ones if needed.

In short, one must be sure of the diagnosis before starting treatment and then modify it as required.