Wojtowicz 2011.

Methods	Study design: randomized, parallel‐group, controlled trial Study site(s): not reported whether single‐ or multi‐center Number randomized (total and per group): 36 participants in total; 21 participants in the omega‐3 treatment group; 15 participants in the control group Unit of randomization (individual or eye): individual Exclusions after randomization: none Losses to follow‐up: none Number analyzed (total and per group): 36 participants in total; 21 participants in the omega‐3 treatment group; 15 participants in the control group Unit of analysis (individual or eye): individual (left eye) Reported power calculation? (Y/N): N Reported subgroup analysis? (Y/N): N
Participants	Baseline characteristics Country: not reported Age (mean ± SD, range): 61 years, range 29 to 84 years Gender: 16 men and 20 women Inclusion criteria: 1. Previous clinical diagnosis of dry eye 2. Positive vital dye staining with 1% lissamine green according to the National Eye Institute/Industry Workshop scale (1995) detected by slit‐lamp examination in the absence of concurrent disease including eyelid or ocular surface inflammation beyond 1+ bulbar conjunctival injection Exclusion criteria: 1. Patients with previous ocular surgery, alterations of the lacrimal drainage system, or eyelid abnormalities 2. Patients with any systemic disease that might affect the ocular surface 3. Pregnant or lactating women 4. Patients using ophthalmic medications or systemic medication affecting tear secretion or lipid metabolism or treatment with commercially available essential fatty acids or vitamin supplements Equivalence of baseline characteristics? (Y/N): Y
Interventions	Intervention #1 (omega‐3 treatment group): oral capsules containing fish oil 1600 mg and flaxseed oil 1000 mg containing eicosapentaenoic acid (EPA) 450 mg, docosahexaenoic acid (DHA) 300 mg (TheraTears Nutrition, Advanced Vision Research) Intervention #2 (control group): placebo ‐ wheat germ oil (dose not reported) Length of follow‐up: 3 months Notes: preservative‐free TheraTears lubricant eye drops were supplied to standardize participants' topical therapy; all participants were instructed to follow their usual diet and to record changes in a diary
Outcomes	Primary and secondary outcome measures were not clearly distinguished Specified outcome(s): OSDI; Schirmer test without anesthesia; TBUT; corneal staining with lissamine green; meibomian gland expressibility; meibum appearance; fluorophotometry; aqueous tear evaporation; meibum lipid analysis, all reported at study endpoint Adverse events reported? (Y/N): N Measurement time points (specify intervals at which outcomes were assessed): baseline, month 3 Other issues with outcome assessment (eg, quality control for outcomes, if any): none
Notes	Study dates: not reported Funding source(s): "supported in part by grants NIH EY12430 and EY016664; an unrestricted grant from the Research to Prevent Blindness, New York, NY; and Advanced Vision Research" Conflicts of interest: not reported Publication language: English Registered on clinical trials registry? (Y/N): N
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of random sequence generation was not reported
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not reported
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"Double‐masked" study "Both active and placebo soft gels appeared identical and were supplied in identical containers for masking purposes" "The patients and study personnel were masked with respect to group assignment to assure accuracy"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"Double‐masked" study "The patients and study personnel were masked with respect to group assignment to assure accuracy"
Incomplete outcome data (attrition bias) All outcomes	Low risk	There were no missing data
Selective reporting (reporting bias)	Unclear risk	No access to study protocol or clinical trials registry
Other bias	Low risk	No other apparent sources of bias

AUF: arbitrary units of fluorescence; BCVA: best‐corrected visual acuity; CIC: conjunctival impression cytology; COX: cyclo‐oxygenase; DESS: Dry Eye Scoring System; DHA: docosahexaenoic acid; EIA: enzyme immunoassay; EPA: eicosapentaenoic acid; FA: fatty acid; FAS: full analysis set; GLA: gamma linolenic acid; HLA‐DR: human leukocyte antigen‐DR; IC: impression cytology; IOP: intraocular pressure; IQR: interquartile ratio; IRB: institutional review board; ITT: intention‐to‐treat; LA: linoleic acid; LASIK: laser‐assisted in situ keratomileusis; MGD: meibomian gland dysfunction; MMP‐9: matrix metalloproteinase‐9; NSAID: non‐steroidal anti‐inflammatory drug; OSDI: Ocular Surface Disease Index; PGE: prostaglandin E; PPS: per‐protocol set; PRK: photorefractive keratectomy; PUFA: polyunsaturated fatty acid; RBS: rose bengal staining; SD: standard deviation; SPEED: Standard Patient Evaluation of Eye Dryness; TBUT: tear break‐up time; VAS: visual analogue scale; VDT: visual display terminal.