Background <p>The study aimed to assess the neuroprotective effect of phospholipid-rich omega-3 fatty acids from herring caviar oil in POAG patients with intraocular pressure (IOP) control.</p> Methods <p>A single-center, observational, short-term, preliminary evaluation of three months was conducted. Fifty eyes of POAG patients with IOP were included and divided into the control group (<i>n</i> = 31) and the intervention group (<i>n</i> = 19) receiving one capsule of omega-3 fatty acids supplementation per day. All the participants underwent comprehensive clinical assessment at baseline and 3&#xa0;months, including best-corrected visual acuity (BCVA), IOP, visual field (VF) test, optical coherence tomography (OCT). Primary outcomes were median deviation (MD) and pattern standard deviation (PSD) scores of VF, while secondary outcomes included BCVA, IOP, retinal nerve fiber layer thickness (RNFLT) of OCT, and adverse events.</p> Results <p>At baseline, no significant differences were observed between the 50 patients in terms of age, sex, antiglaucomatous medications, BCVA, IOP, VF, or RNFLT. After three months, the intervention group exhibited a statistically significant improvement in MD value (<i>p</i> = 0.01). The change of PSD revealed a slightly greater reduction in the intervention group compared to controls, albeit with borderline significance (<i>p</i> = 0.08). A minor decrease in IOP was noted in the intervention group at three months, compared to the control group (<i>p</i> = 0.07). No significant differences were observed in other secondary outcomes, and no adverse events were reported.</p> Conclusion <p>Oral omega-3 fatty acids supplementation derived from herring caviar oil is potentially neuroprotective and safe for IOP-controlled POAG patients, and it may serve as a clinically valuable additional option. However, these results necessitate confirmation with an appropriately designed randomized controlled study.</p>