Six months of supplemental use of gamma-linolenic acid (GLA) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) improves ocular irritation symptoms, maintains corneal surface smoothness and inhibits conjunctival dendritic cell maturation in postmenopausal patients with keratoconjunctivitis sicca, a recent study reports.
Notably, the study also suggests that long-term supplementation reduces the inflammation and pain associated with dry eye.
Conducted by John D. Sheppard, MD, et al., the study examined the effect long-term supplementation with GLA and n-3 PUFAs had on the production of inflammatory mediators implicated in the pathogenesis of chronic dry eye. The six-month, multicenter, double-masked clinical trial, published in the October 2013 edition of Cornea, randomly supplemented 38 postmenopausal tear dysfunction patients with either GLA and n-3 PUFAs or a placebo.
Subjects had a number of disease parameters assessed at baseline, and then again at four, 12 and 24 weeks. The parameters assessed included Ocular Surface Disease Index (OSDI), Schirmer test, tear breakup time, conjunctival fluorescein and lissamine green staining, and topographic corneal smoothness indexes. Conjunctival impression cytologies were also used to measure dendritic cell CD11c integrin intensity and HLA-DR expression in subjects.
After 24 weeks, the OSDI score showed significant improvement following supplementation (21 ± 4) when compared to placebo (34 ± 5). Surface asymmetry index also showed improvement at the 24-week mark in the supplemented patients (0.37 ± 0.03) vs. placebo (0.51 ± 0.03). Neither treatment was found to have any effect on tear production, tear breakup time, or corneal or conjunctival staining.
Also, placebo treatment showed a significant increase in both HLA-DR intensity (36% ± 9%) and CD11c intensity (34% ± 7%) after 24 weeks. The stability in HLA-DR expression observed in the supplement-treated subjects may suggest a gradual mitigation of inflammation, but further studies must be conducted before this is confirmed.
The researchers did not evaluate pain associated with KCS, but the OSDI includes criteria for pain assessment. These scores associated with pain showed significant improvement in KCS patients following supplementation.
Sheppard JD Jr, Singh R, McClellan AJ, et al. Long-term supplementation with n-6 and n-3 PUFAs improves moderate-to-severe keratoconjunctivitis sicca: A randomized double-blind clinical trial. Cornea. 2013 Oct; 32(10):1297-1304.