Kangari 2013.

Methods	Study design: randomized, parallel‐group, controlled trial Study site(s): single center Number randomized (total and per group): 146 eyes of 73 participants; 72 eyes of 38 participants in the treatment group; 70 eyes of 35 participants in the control group Unit of randomization (individual or eye): individual Exclusions after randomization: 3 participants discontinued due to digestion problems, and 1 participant discontinued due to the advice of another doctor in the treatment group Losses to follow‐up: 1 participant in the treatment group; 4 participants in the control group Number analyzed (total and per group): 64 participants in total; 33 participants in the treatment group; 31 participants in the control group Unit of analysis (individual or eye): individual (average of both eyes) Reported power calculation? (Y/N): Y (80% power) Reported subgroup analysis? (Y/N): N
Participants	Baseline characteristics: Country: Iran Age (mean ± SD, range): 60.6 ± 8.7 years in the treatment group; 61.8± 8.0 years in the control group Gender: 15 men and 18 women in the treatment group; 11 men and 20 women in the control group Inclusion criteria: 1. Aged 45 to 90 years 2. TBUT < 10 seconds in both eyes 3. No use of artificial tears for the past 3 months Exclusion criteria: 1. Active allergy or infection at the ocular surface 2. Presence of pterygium or pinguecula 3. Treatment with ocular topical steroidal or non‐steroidal anti‐inflammatory treatment, glaucoma medication, or antiallergy eye drop in the past month 4. Positive history of refractive surgery or contact lens wear 5. Use of a systemic medication that may interfere with tear production, such as antianxiety, antidepressive, antihypertensive, and antihistamine medications 6. Positive history of blood or coagulation disorders 7. Positive history of gastric ulcers 8. Positive history of surgery in the past 3 months 9. Undergoing head and neck radiotherapy 10. Use of omega‐3 supplements in the past 3 months 11. Positive history of allergy to fish oil or gelatinous capsules Equivalence of baseline characteristics? (Y/N): Y
Interventions	Intervention #1 (treatment group): oral capsule containing eicosapentaenoic acid 180 mg and docosahexaenoic acid 120 mg, twice daily (daily dose of eicosapentaenoic acid 360 mg and docosahexaenoic acid 240 mg) Intervention #2 (control group): placebo capsule containing medium‐chain triglyceride oil (Zahravi Pharmaceutical Company), 2 × 1 g capsules per day, twice daily Length of follow‐up: 1 month Notes: none
Outcomes	Primary outcome(s): "increase from baseline" in TBUT; however both outcomes appear to be reported as endpoint data at the end of the follow‐up period Secondary outcome(s): "decrease from baseline" in OSDI score; "increase from baseline" in Schirmer test without anesthetic; however both outcomes appear to be reported as endpoint data at the end of the follow‐up period Adverse events reported? (Y/N): Y Measurement time points (specify intervals at which outcomes were assessed): baseline, 1 month Other issues with outcome assessment (eg, quality control for outcomes, if any): none
Notes	Study dates: not reported Funding source(s): "this project is funded by the Vice Chancellor for Research of Shahid Beheshti University of Medical Sciences" Conflicts of interest: "the author(s) have no proprietary or commercial interest in any materials discussed in this article" Publication language: English Registered on clinical trials registry? (Y/N): Y ‐ clinical trial registry (IRCT201012265467N1)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"The method of randomization in this study was blocked randomization. Thirteen blocks of 6 were determined" However the method used to generate the random sequence is not reported
Allocation concealment (selection bias)	Low risk	"To avoid information bias, omega‐3 allocation was performed in a double‐blind fashion; the treatment group, the control group, and the examiners who performed the tests were all unaware of the allocation status. Patients were coded by a third person who applied the randomization protocol and provided them with the allocated type of capsules"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"To avoid information bias, omega‐3 allocation was performed in a double‐blind fashion; the treatment group, the control group, and the examiners who performed the tests were all unaware of the allocation status. Patients were coded by a third person who applied the randomization protocol and provided them with the allocated type of capsules" "The placebo capsules were prepared by the Zahravi Pharmaceutical Company (Tehran, Iran) and appeared exactly like the omega‐3 capsules"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"To avoid information bias, omega‐3 allocation was performed in a double‐blind fashion; the treatment group, the control group, and the examiners who performed the tests were all unaware of the allocation status. Patients were coded by a third person who applied the randomization protocol and provided them with the allocated type of capsules"
Incomplete outcome data (attrition bias) All outcomes	High risk	"A total of 9 subjects (5 in the treatment group, 4 in the control group) failed to complete the trial; in the treatment group, 3 subjects stopped the medication because of digestion problems, 1 subject stopped the medication because of the advice of another doctor, and the rest of the subjects were lost to follow‐up" 9/73 (12.3%) participants who were randomized were not included in the analysis
Selective reporting (reporting bias)	Low risk	All prespecified outcomes on the trial registry were reported in the paper
Other bias	Low risk	No other apparent sources of bias