In a new study published in JAMA Ophthalmology, researchers investigated the effectiveness of systemic re-esterified triglyceride (rTG) omega-3 (ω-3) fatty acids for treating dry eye disease (DED) with meibomian gland dysfunction (MGD) compared to grape-seed oil.
Give me some background first.
DED is a multifactoral disease often associated with symptoms such as:
- Eyes feeling a stinging or burning sensation
- Blurred vision
- Pain while wearing contact lenses
- Scratchy or gritty feeling like something is in the eye
- Red or irritated eyes
- High volume of tears in the eyes
And the research on omega-3s?
Previous studies have found that oral consumption of re-esterified ω-3 fatty acids was associated with significant improvement in tear osmolarity, omega-3 index levels, tear break-up time (TBUT), Matrix Metalloproteinase-9 (MMP-9), and ocular surface disease index (OSDI) symptom scores.
However, another recent clinical trial concluded that ω-3 fatty acids were not effective for treating DED.
Now, talk about the study.
Researchers conducted a randomized clinical trial (RCT) with Korean participants. The trial was conducted at seven medical institutions between September 21, 2020, and January 19, 2023.
These institutions included:
- Korea University Ansan Hospital
- Wonju Severance Christian Hospital
- Seoul National University Bundang Hospital
- Asan Medical Center
- Yonsei University Severance Hospital
- Kangbuk Samsung Hospital
- Seoul National University Hospital
Participant details, please?
The study included 132 participants diagnosed with DED with concurrent MGD. Patient demographics were:
- Mean (Standard Deviation [SD]) age, 50.6 (13.8) years
- 103 females (78.0%)
- 29 males (22.0%)
How was the study conducted?
Participants were randomly assigned to the ω-3 group and grape-seed groups in a 1:1 ratio.
Participants in the ω-3 group received the following at a dose of four capsules per day (QID):
- ω-3 supplement capsule containing:
- 1680 mg of eicosapentaenoic acid (EPA)
- 560 mg of docosahexaenoic acid (DHA)
Participants in the grape-seed group received the following dosage QID:
- 3000 mg of 100% grape-seed oil
Note: Both groups were prescribed preservative-free hyaluronic acid, 0.1% or 0.15%, eye drops that they were instructed to use as needed to relieve dry eye symptoms up to six times per day.
Findings?
The following number of participants completed 12 weeks of follow-up:
- 58 patients (87.9%) in the ω-3 group
- 57 patients (86.4%) in the grape-seed groups
There were no differences in compliance with the dietary supplement intake between the groups:
- 95.8% for the ω-3 group
- 95.4% for the grape-seed group
Additionally, there were no changes in safety parameters or adverse events (ARs) related to taking the dietary supplement in either group.
What was the data regarding OSDI scores?
Mean (SD) baseline OSDI scores of the groups were:
- 43.5 (16.5) for the ω-3 group
- 44.1 (16.6) for the grape-seed group
The mean (SD) OSDI change from baseline to 6 and 12 weeks was:
- −20.5 (16.0) and −22.7 (15.7), respectively, in the ω-3 group
- −15.1 (20.2) and −18.8 (21.7), respectively, in the grape-seed control group
- Difference at 6 weeks = −5.4; 95% CI, −12.15 to 1.33; P = .12
- Difference at 12 weeks = −3.9; 95% CI, −10.90 to 3.13; P = .28
Note: The OSDI assesses the impact of dry eye symptoms on a patient’s quality of life (QOL) in the past week. A final score is calculated from 0 to 100 with scores representing:
- Normal: 0 to 12
- Mild DED: 13 to 22
- Moderate DED: 23 to 32
- Severe DED: >33
Limitations?
Limitations included the short follow-up period and small sample size. The authors also noted that the control group was not a placebo group, which may have caused limitations in interpreting the clinical relevance of the results.
Also: While the dietary supplements were contained in identical gel capsules and bottles for concealment, if a participant had popped a gel capsule, they might have been able to taste a difference.
Lastly, there was the potential for selection bias, as per-protocol analysis was performed without imputation.
Expert opinion?
The authors recommended additional research to investigate the effectiveness of systemic rTG ω-3 fatty acids for the treatment of DED associated with MGD.
They stated, “Any secondary outcomes from this study should be considered for hypothesis generation of future evaluations of the role of the rTG form of ω-3 on DED associated with MGD.”
Take home.
Ultimately, the rTG form of ω-3 did not provide any improvements to symptoms of DED associated with MGD.