Aim: To evaluate the role of dietary supplementation of omega-3 fatty acids in dry eye syndrome.
Methods: A prospective, interventional, placebo controlled, double blind randomized trial was done at two referral eye centers. Two hundred and sixty-four eyes of patients with dry eye were randomized to receive one capsule (500mg) two times a day containing 325mg EPA and 175mg DHA for 3 months (omega-3 group). The omega-3 group was compared to a group of patients (n=254) who received a placebo (placebo group). There were 4 patient visits (at baseline, 1 month, 2 months and 3 months). On each visit, recording of corrected distance visual acuity (CDVA), slit lamp examination and questionnaire based symptom evaluation and scoring was done. A symptomatic score of 0-6 was mild, 6.1-12 moderate and 12.1-18 severe dry eye. Response to intervention was monitored by routine tear function tests like Schirmer I test, tear film break-up time (TBUT), Rose Bengal staining and most notably, conjunctival impression cytology.
Results: Sixty-five percent of patients in the omega-3 group and 33% of patients in placebo group had significant improvement in symptoms at 3 months (P=0.005). There was a significant change in both Schirmer's test value and TBUT values in the omega-3 group (P<0.001), both comparisons. However, there was a larger drift in TBUT values in omega-3 than the placebo group, in comparison to Schirmer's test values. The mean TBUT score was 2.54±2.34 in the omega-3 group and 0.13±0.16 in placebo group, respectively. The mean reduction in symptom score in omega-3 group was 2.02±0.96 as compared to 0.48±0.22 in placebo group (P<0.001). Despite a slight increase mean score, the Schirmer scores did not correlate well with symptomatic improvement.
Conclusion: Omega-3 fatty acids have a definite role for dry eye syndrome. The benefit seems to be more marked in conditions such as blepharitis and meibomian gland disease. The role of omega fatty acids in tear production and secretion needs further evaluation.
Keywords: conjunctival impression cytology; dry eye syndrome; meibomian gland disease; omega-3 fatty acids.