Friday, February 24, 2012
Mark R. Levine, MD
Once a diagnosis of dry eyes is made, the treatment focus should be not just volume deficiency but also the evaporative state. That is to say, the quality of the meibomian glands, be it increased turbidity to outright cottage cheese appearance, is paramount to a successful outcome. More than 50% of the time, there is a combination of both. Therefore, recognize and treat both.
There are a number of artificial tears on the market, with no one tear substitute standing out on a constant basis. Frequent use is essential (five to six times a day) for supplementing volume, reducing hyperosmolarity and diluting out bacteria and cytokines present in the meibomian glands.
A gel at bedtime or a vaporizer by the bedside is helpful for patients who awaken during the night or in the morning with ocular discomfort.
Restasis (topical cyclosporine 0.05%, Allergan) for more difficult cases is most effective in increasing tear production, decreasing cytokine production, improving meibomian gland secretions, increasing goblet cells and diminishing lid margin vascularity. It is used twice a day for at least 2 years to avoid regression.
More frequent use of tears, especially with a computer dry eye component, necessitates preservative-free substitutes. Punctal plugs are also additive, providing the evaporative component has been treated so there is not a buildup of bacteria and cytokines irritating the ocular surface.
My choice of plugs are surface plugs, even though they can be wiped out or fall out. Success with punctal plugs can be replaced with sequential punctal cautery. In my experience, intracanalicular plugs can be more problematic than helpful. There are small series of cases of intracanalicular plugs causing canaliculitis and nasal lacrimal duct obstruction.
Dysfunctional meibomian glands increase tear evaporation and produce bacteria and cytokines on the ocular surface. Nighttime warm compresses, eyelid massage and removal of anterior blepharitis with a wet cotton swab followed by installation of antibiotic ointment for a month are most helpful. I happen to like erythromycin ointment at bedtime. It is very affordable compared with other ointments, and it is antibacterial and anti-inflammatory. It works more often than not. At the end of 1 month, reassess and continue with the same or change to an antibiotic steroid combination of your choosing. Remember, patients can be allergic to all these antibiotics. Let the patients know that so they discontinue use if their eyes are red and itchy.
In my opinion, the use of fish or flaxseed oil in conjunction with antibiotics is critical. Omega-3 is anti-inflammatory to the ocular surface, reduces cytokine production and helps reconstitute the meibomian glands. Depending upon patient response, doxycycline or minocycline 50 mg to 100 mg may be substituted. The drug reduces bacterial lipase, altering the fatty acid composition, and inhibits collagenase. Tetracyclines have a lot to offer on paper, but I have not been that clinically impressed.
The use of steroids in more difficult patients with a lot of ocular surface disease is most helpful. This can range from loteprednol etabonate to prednisolone drops, twice a day to four times a day. Judicious use is recommended.
Finally, eyelid malpositions such as lid retraction, ectropion and entropion need to addressed to decrease the evaporative surface as well as calm it.
Does this always work? Definitely not, but it goes a long way in improving the patients' comfort. Needless to say, some of the toughest cases are dry eye patients with glaucoma, as the benzalkonium chloride in glaucoma medications can be toxic to the corneal surface. Preservative-free pharmacy-made drops and laser trabeculoplasties can improve the situation.
Remember, an improved ocular surface, be it through cataract, glaucoma or oculoplastics procedures, makes for a happier postoperative patient.
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