Dry eye disease, a chronic condition where the eyes don’t produce enough quality tears to stay lubricated, is often driven by ongoing low-grade inflammation of the ocular surface. Because palmitoylethanolamide (PEA) has a long research history as an anti-inflammatory compound in ophthalmology, mostly in glaucoma and retinal disease, some of that research has extended specifically into ocular surface inflammation and dry eye. This article covers what the topical and preclinical PEA research for dry eye actually shows, and how it differs from PEA’s better-known oral supplement research for chronic pain conditions covered elsewhere on this site.
It’s important to be precise about what has and hasn’t been studied here. Human PEA research for eye conditions includes oral PEA trials for eye pressure in glaucoma, while the topical human data are limited to small studies of ocular surface inflammation, and no human trial in dry eye disease itself is described here [3]. Nothing here is a substitute for an eye care professional’s evaluation, and PEA is not an FDA-approved treatment for dry eye disease.
Key Takeaways
- A pilot clinical trial in glaucoma patients with medication-related ocular surface inflammation found that, in a small pilot with no placebo group, tear film breakup time and the Schirmer test, two standard clinical measures of dry eye severity, improved from baseline after topical PEA eye drops [3][1].
- A preclinical study found that sleep deprivation reduces natural PEA levels in the lacrimal gland (the gland that produces tears), and that restoring PEA levels improved dry eye signs in an animal model [2].
- The dry-eye-related PEA work described here is one small pilot of topical eye drops in glaucoma-drop surface inflammation and a mouse study; oral PEA has not been tested for dry eye [3][2].
- PEA’s proposed mechanism in the eye is similar to its mechanism elsewhere in the body: dampening mast cell activation and inflammatory signaling at the ocular surface.
- This is an emerging research area with a smaller and earlier-stage evidence base than PEA’s pain-focused research, and topical PEA eye drop products are not widely available as an over-the-counter category in the way oral PEA supplements are.
The Pilot Trial in Glaucoma-Related Ocular Surface Disease
The most directly relevant human trial tested a topical PEA formulation (marketed as Defluxa) in glaucoma patients whose long-term use of hypotensive eye drops had caused chronic ocular surface inflammation, a common and under-treated side effect of glaucoma management [1]. In this pilot trial, 15 patients received topical PEA in addition to their existing glaucoma medications, while 15 patients continued their existing treatment alone. Researchers assessed the Schirmer test, tear film breakup time, and conjunctival hyperemia at baseline, day 15, and day 30.
By day 30, the PEA group showed statistically significant improvements in the Schirmer test and tear film breakup time compared to baseline, and conjunctival hyperemia (redness) was significantly reduced compared to the control group as early as day 15. In this small pilot, which had no placebo group, the researchers concluded that topical PEA was well tolerated and suppressed the ocular surface inflammation associated with chronic glaucoma drop use [3].
What the Preclinical Sleep Deprivation Research Adds
A separate line of research looked at why dry eye develops in the first place from a PEA perspective. Using a mouse model, researchers found that sleep deprivation reduced the natural production of PEA in the lacrimal gland, largely due to decreased activity of the enzyme responsible for synthesizing it [2]. This drop in local PEA was linked to lipid buildup, gland dysfunction, and reduced tear production, the same processes seen in human dry eye disease. When researchers restored PEA levels in the sleep-deprived mice, corneal barrier function improved and dry eye clinical signs were reduced.
Research note: In rabbits, a nanoparticle PEA eye drop raised PEA levels in the vitreous and retina well above a plain PEA suspension [4].
This preclinical study doesn’t test a PEA supplement or eye drop in humans with dry eye, it’s mechanistic research explaining a biological pathway. But it does help explain why topical PEA might work in the human ocular surface trial above: it is possible, though unproven, that topical PEA works by replacing a protective compound the eye already makes; the mouse findings do not show this in people [2].
Topical Eye Drops vs Oral PEA Supplements
This is the most important distinction for anyone reading this site’s other PEA content and wondering if their oral capsules will help dry eyes. The human dry-eye-relevant trial used a topical eye drop formulation applied directly to the ocular surface, not an oral supplement. Oral PEA, the form covered throughout the rest of this site for pain conditions like fibromyalgia and neuropathy, has not been specifically tested in human dry eye trials. It’s plausible that systemic anti-inflammatory effects from oral PEA could indirectly support ocular surface health, but that is an extrapolation from PEA’s general mechanism, not something the dry eye trials above actually tested.
Topical PEA eye drop products are not a mainstream, widely available over-the-counter category in the way oral PEA capsules are. Formulations studied in the research above, such as Defluxa, are specialty or prescription-adjacent products used mainly in Europe rather than something typically found alongside standard artificial tears.
What This Means for Someone With Dry Eye
The evidence so far is a hypothesis for dry eye, based on one small pilot in medication-related ocular surface inflammation in glaucoma patients and a mouse study, and it is not established [3][2] as a first-line or standalone dry eye treatment. Standard dry eye management, artificial tears, addressing environmental triggers, treating meibomian gland dysfunction, and prescription options like cyclosporine or lifitegrast when appropriate, remains the foundation of care. Anyone with persistent dry eye symptoms should be evaluated by an eye care professional, since dry eye has multiple distinct underlying causes that require different treatment approaches.
Frequently Asked Questions
Can I use my oral PEA supplement as eye drops?
No. Oral PEA capsules are formulated for ingestion, not ocular use, and should never be applied directly to the eyes. The topical PEA research discussed here used specifically formulated ophthalmic preparations, not repurposed oral supplements.
Does oral PEA help with dry eyes?
This has not been directly tested in human trials. The dry-eye-relevant PEA research to date has focused on topical eye drop formulations and preclinical animal models, not oral supplementation for dry eye specifically.
Is topical PEA available over the counter for dry eye?
Topical PEA eye drop formulations like Defluxa are not a mainstream over-the-counter category in most markets and are used mainly in specialty or European ophthalmology settings rather than sold alongside standard artificial tears.
What causes dry eye disease?
Dry eye can result from insufficient tear production, poor tear quality, meibomian gland dysfunction, environmental factors, certain medications, and chronic inflammation of the ocular surface. An eye care professional can help identify which factors are contributing in an individual case.
References
- Di Zazzo A, et al. Use of Topical Cannabinomimetic Palmitoylethanolamide in Ocular Surface Disease Associated with Antiglaucoma Medications. J Clin Med (2017). PMID 29045169
- Chen Q, Ji C, Zheng R, et al. N-Palmitoylethanolamine Maintains Local Lipid Homeostasis to Relieve Sleep Deprivation-Induced Dry Eye Syndrome. Front Pharmacol (2020). PMID 32047441
- Liu Z et al. Nutraceuticals and neuroprotection for glaucoma-introducing the NP-10 System. Therapeutic advances in ophthalmology (2025). PMID 41280204
- Puglia C et al. Innovative Nanoparticles Enhance N-Palmitoylethanolamide Intraocular Delivery. Frontiers in pharmacology (2018). PMID 29643808
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.