The prevalence of dry eye increases with age and may be as high as 30% of the population age 50 years or older. Women are more likely to have it than men. Other common risk factors include contact lens use, medications (e.g., antihistamines, SSRIs, anticholinergics), tobacco use, diabetes, and ophthalmic surgery.
Patients will present with eye irritation, a foreign body sensation, excessive tearing, and altered vision. If you are like me, you will do a general nondilated ophthalmologic exam and, seeing nothing grossly abnormal, recommend artificial tears in disposable-unit–dose aliquots. But before recommending a subspecialty consult, is there anything else that we can do?
Recall that the tear film of the eye is made up of aqueous, mucous, and lipid components. Some of us might be aware of the literature suggesting patients with high intake of n-3 (or "omega-3") polyunsaturated fatty acids (i.e., fish oil) have lower rates of dry eyes. Fish oil may enhance the tear lipid layer and increase tear stability.
So, does giving fish oil supplementation to patients decrease dry eye symptoms?
Dr. Tetsuya Kawakita of Keio University, Tokyo, and his colleagues conducted a randomized trial of the effectiveness of fish oil capsules containing EPA (eicosapentaenoic acid) 1,245 mg/day and DHA (docosahexaenoic acid) 540 mg/day for the relief of dry eye symptoms (Biomed. Res. 2013;34:215-20).
Patients were eligible for enrollment if they were at least 40 years of age and had dry eye symptoms, abnormal tear production (Schirmer test), or presence of tear film instability (tear break-up time) and positive ocular rose bengal staining or fluorescein vital staining. Patients took five fish oil capsules at breakfast, lunch, and dinner (15 capsules per day) or matching placebo for 12 weeks, with a 4-week wash out period. Objective and subjective measures of dry eye were used as outcomes.
A total of 27 patients were randomized, and data from 26 were used (15 fish oil patients, 11 placebo patients).
Fish oil was associated with significantly reduced eye pain, compared with placebo, as well as significant prolongation of tear-film break-up time. There were no significant differences in the two groups’ Schirmer test results, rose bengal staining scores, or fluorescein vital staining scores.
Thus, fish oil supplementation may be helpful for the treatment of dry eyes. However, 15 pills a day seems like a lot. We could seek to find the lowest effective dose that our patients can tolerate. For patients who have gastrointestinal distress (i.e., "fish burps") from fish oil tablets, I have learned that keeping them in the freezer and swallowing the pills frozen helps. For patients who do not tolerate the nausea that occasionally accompanies high fish oil doses, new preparations of fish oil are available.
Dr. Ebbert is professor of medicine, a general internist at the Mayo Clinic in Rochester, Minn. The opinions expressed are those of the author. He reports no conflicts of interest.