# The Protective Effect of Polyunsaturated Fatty Acids against Dry Eye Disease: A Literature Review
## 4 Current Perspectives  
Evidence accumulated from studies conducted within the past decades indicates that supplementation with PUFAs, particularly \(\omega 3\), may help the treatment of DED [85]. The report of the 2007 dry eye workshop (DEWS) indicated increased dietary \(\omega 6\omega 3\) ratio and decreased consumption of \(\omega 3\) PUFAs as risk factors for DED [86]. The DEWS II report in 2017 also listed low PUFA intake as a probable risk factors for DED [7]. A consensus panel for clinical guidelines recommended oral \(\omega 3\) PUFA supplementation for the management of moderate DED [87]. The recommendation by the Practicing Ophthalmologists Curriculum from the American Academy of Ophthalmology also included systemic \(\omega 3\) PUFA administration as the treatment of MGD and blebaritis [88]. The daily intake of a moderate dose of \(\omega 3\) was also shown to have beneficial effect against MGD [84]. Meanwhile, the safety profiles of PUFA have not been paid much attention to, as studies regarding the PUFA supplementation in patients with DED have rarely reported adverse effects of the PUFAs [85]. However, no formal consensus has been established for the optimal protocol of PUFA supplementation, which comprises the composition and dose of the supplements and the duration of treatment [89]. This has been attributed to the following reasons. (1) Clinical trials have had considerably heterogeneous compositions, doses, and durations, making it difficult to establish guidelines [85]. (2) There are few well-controlled long-term clinical trials involving a large population. An epidemiological study indicated that over 80% of adults in developed countries may have \(\omega 3\) PUFAs deficiency [90], and the American Dietetic Association (ADA) recommended the daily intake of 500 mg of \(\omega 3\) PUFAs [91]. PUFAs are also suggested to \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Study** & **Design** & **Level** & **Sample Size** & **Daily Dose** & **Duration** & **Objective and Subjective** \\  & & & & & & & **Study Outcomes** \\ \hline [PERSON] et al. [77] & Prospective comparative study & II & 57 & 15 mg GLA + 28.5 mg LA & 6 months & improved symptoms of MGD, Reduced lid margin inflammation \\ [PERSON] et al. [78] & RCT & I & 38 & 6000 mg dissected oil (3300 mg \(\omega 3\)) & 12 months & Decreased symptom score of DED, Improved TBUT and meibum score \\ [PERSON] et al. [79] (2013) & RCT & I & 518 & 650 mg ERA + 350 mg DHA & 3 months & Decreased cry eye symptoms, Improved tear stability \\ [PERSON] et al. [22] (2016) & RCT & I & 130 (Rosacea) & 720 mg ERA + 480 & 6 months & Improved symptoms, tear stability and meibomian gland score \\ [PERSON] et al. [80] & RCT & I & 64 & 1275 mg ERA + 1050 mg DHA & 3 months & Improved signs and symptoms of MGD, Improved tear stability \\ [PERSON] et al. [81] (2016) & RCT & I & 105 & 1680 mg ERA + 350 mg DHA & 3 months & Improved tear stability, Decreased score of dry eye symptoms \\ [PERSON] et al. [82] & RCT & I & 26 & 2000 mg \(\omega 3\) & 3 months & Improved neibomian gland, functionality, and dry eye symptoms \\ (2015) & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of the studies on the efficacy of \(\omega 3\) PUFAs on MGD. be able to lower the risk of coronary stroke, mainly by reducing blood cholesterol level, and also have shown promising effects against cancer, diabetes, and depression [92]. The American Heart Association (AHA) recommended diet with at least two servings of fish a week and consumption of foods containing high amount of \(\omega\)3 PUFAs for the prevention of cardiovascular diseases, which is also conceivably beneficial for the prevention of DED [93]. High doses of \(\omega\)3 PUFAs of 200-2200 mg per day were shown to be beneficial for the improvement of psychological symptoms, including anxiety and depression [94,95]. These findings indicate a high dose of oral \(\omega\)3 PUFA supplementation can also be advantageous for the patients with DED [96].