Association between very long chain fatty acids in the meibomian gland and dry eye resulting from n-3 fatty acid deficiency.

In our previously study, we reported lower tear volume in with an n-3 fatty acid deficient mice and that the docosahexaenoic acid and total n-3 fatty acid levels in these mice are significantly reduced in the meibomian gland, which secretes an oily tear product. Furthermore, we noted very long chain fatty acids (≥25 carbons) in the meibomian gland. To verify the detailed mechanism of the low tear volume in the n-3 fatty acid-deficient mice, we identified the very long chain fatty acids in the meibomian gland, measured the fatty acid composition in the tear product. Very long chain fatty acids were found to exist as monoesters. In particular, very long chain fatty acids with 25-29 carbons existed for the most part as iso or anteiso branched-chain fatty acids. n-3 fatty acid deficiency was decreased the amount of meibum secretion from meibomian gland without change of fatty acid composition. These results suggest that the n-3 fatty acid deficiency causes the enhancement of evaporation of tear film by reducing oily tear secretion along with the decrease of meibomian gland function.

[Clinical evaluation of a thermodynamic treatment system for meibomian gland dysfunction].

OBJECTIVE: To evaluate the effectiveness and safety of a single thermodynamic treatment system (LipiFlow) for meibomian gland dysfunction (MGD). METHODS: Retrospective series case study. Forty-eight subjects with meibomian gland dysfunction were analyzed before and after 12 minutes LipiFlow system treatment. All subjects were examined before, 4 weeks and 12 weeks after this treatment. Subjective symptoms, lipid layer thickness (LLT), expressible meibomian gland, tear break-up time, meibomian gland assessment and ocular surface staining were measured. Statistical analysis was performed using SPSS 11.5 software. Analysis included those independent sample two-tailed t-tests for comparison of the mean change from baseline to 4 weeks and baseline to 12 weeks after Lipiflow treatment. Statistically significant difference was based on α=0.05 (P<0.05). RESULTS: A total of 48 cases completed the 12-week follow-up. MGD patients with LipiFlow treatment had a significant reduction in the Ocular Surface Disease Index (OSDI) scores with 45.36±19.34 before treatment, 23.82±11.94 at 4 weeks (t=2.009, P=0.035) and 25.66±14.12 at 12 weeks (t=1.976 P=0.038). LipiFlow resulted in a higher number of expressible glands from 2.91±1.13 (baseline) to 6.27±2.37 (4 weeks, t=3.505, P<0.001) and 5.15±2.08 (12 weeks, t=2.004, P= 0.027) and change of secretion quality from 6.18±2.48 (baseline) to 13.55±3.46 (4 weeks,t=2.698,P=0.005) and 12.67±3.41 (12 weeks,t=2.403,P=0.009). In addition, a single thermodynamic treatment increase the LLT from (42.13±9.67)nm (baseline) to (59.02±16.39)nm (4 weeks, t=2.971, P=0.002) and (54.65±12.52)nm (12 weeks, t=2.021, P=0.021). The rate of partial blink was relieved from 0.37±0.30 (baseline) to 0.15±0.14 (4 weeks, t=3.428, P=0.035) and 0.12±0.13 (12 weeks, t=1.986, P=0.026). BUT was increased from (4.73± 2.34)s (baseline) to (9.32 ± 2.18)s (4 weeks, t=3.385, P<0.001) and (9.91 ± 3.01)s (12 weeks, t=3.253, P< 0.001). There were no unanticipated or serious device-related adverse events reported. Compared with baseline, there was no statistically significant difference in BCVA, corneal staining and intraocular pressure (P=0.141, 0.376, 0.421). CONCLUSION: The LipiFlow system was a safety and effectiveness treatment of MGD in the 12-week study.