Coach — Dry Eye and the Ocular Surface: A Metabolic Hypothesis
Dry, gritty, burning eyes are among the most common complaints in any eye clinic. The usual names are meibomian gland dysfunction (MGD), dry eye (keratoconjunctivitis sicca), blepharitis, and ocular rosacea. The usual story is that the eye is short of tears or that local immune cells are overactive. This essay offers a different reading: on this hypothesis, these are hard-working tissues that start to fail when their mitochondria cannot make enough energy, and the modern diet is a large part of why. Artificial tears, punctal plugs, warm compresses, and immune-calming drops such as cyclosporine and lifitegrast ease the symptoms, but on this view they work downstream and leave the energy shortfall in place.
An expensive surface
The front of the eye is costly to run. The meibomian glands in the eyelids build a complex oily layer that keeps tears from evaporating, and that work depends on steady mitochondrial energy and on NAD+. The tear glands must make watery tears with the right salt balance, and the surface cells must keep a tight barrier and repair quickly. On this hypothesis, when energy runs short, the oil turns thicker and waxier, it flows less easily, the barrier leaks, and local inflammation starts. Those changes may be what later get named obstructive MGD, evaporative dry eye, or blepharitis. Salty, evaporating tears then damage mitochondria further, and the damage feeds inflammation in a loop. The cell’s energy sensor, AMPK, is turned down in the glands under high blood sugar; in one study of diabetic rats, restoring it with high-dose metformin protected the glands; this has not been tested in people. Metformin is a prescription drug; here it appears only as a finding from one high-dose rat study, untested for this use in people, and any question about it belongs with your own physician.
Diet and the wider body
The main modern driver, on this hypothesis, is diet: constant refined carbohydrate and too much linoleic acid may push mitochondria into strained, inefficient modes, followed by insulin resistance and low-grade inflammation. The glands that make oil and tears then work under that same strain. Studies link high blood sugar, abnormal blood fats, and high blood pressure with more dry eye, and diabetes with more MGD. In diabetic rats, high blood sugar damaged the glands within months; in mice, Western-style high-fat feeding damaged them too, and those changes improved when the diet was corrected. These are animal studies, not tested in people. The essay reads all of this as the same energy shortfall seen in muscle, liver, and brain.
Ocular rosacea
This essay proposes that ocular rosacea is less a skin disease that spreads to the eyelids than an expression of the same energy shortfall. The facial oil glands and the meibomian glands share programs and energy needs, so on this view the same shortfall shows up in both: redness and bumps on the face, thick oil and dry eye at the lids. Eye signs can come before the skin signs. Rosacea is linked with abnormal blood fats, inflammation markers, and oxidative stress, and, in one small, partly unblinded study, with small-intestinal bacterial overgrowth, whose treatment cleared or greatly improved the skin in most of those treated; that has not been shown for the eye. On this view, Demodex mites and microbial shifts act mainly as amplifiers; Demodex blepharitis still has its own physician-directed treatment.
Why the usual treatments stay downstream
On this hypothesis, inflammation here is largely the body’s response, not the first cause. Prescription immune-calming drops can improve symptoms and signs, and plugs save the tears that remain, but on this view neither restores the glands’ energy supply. The result is often a condition that is managed rather than resolved.
Pillars first, then extras
The essay starts with the three EnSurf pillars: Fuel that favors clean burning and cuts refined carbohydrate and excess linoleic acid, Circadian alignment, and Strength. Only after those does it discuss extras that may add to what the pillars build.
Astaxanthin is proposed to work on oxidative stress. In one small, month-long open-label study without a placebo group, dry-eye symptoms and gland signs improved while tear volume and gland dropout did not change; the study amount is on the Sage page as information only. NAD precursors come up because, in aged mice, falling NAD+ slows an enzyme the glands use to make their own local steroid hormones; NAD precursor eye drops partly restored gland size in those mice. Whether oral precursors would help the glands in people has not been tested. CoQ10 eye drops combined with cross-linked hyaluronic acid did better than plain hyaluronic acid in one small trial, though the different base makes it hard to credit CoQ10 alone; oral CoQ10 has not been tested for dry eye. Methylene blue is discussed as an electron carrier that, in laboratory studies, may bypass weak links in the energy chain, with higher amounts turning harmful. It carries an FDA boxed warning for serotonin syndrome with SSRIs, SNRIs, MAOIs and other serotonergic drugs, and it is avoided in G6PD deficiency and pregnancy; any use belongs with your own physician. On EnSurf it is information only, within the three windows on the Methylene Blue page, and nothing here is a recommendation.
A GLA-plus-omega-3 formula such as HydroEye is proposed to supply building blocks for the oil layer. One small placebo-controlled trial in postmenopausal women with dry eye found better symptom scores and calmer surface inflammation markers than placebo, while tear production, tear breakup time, and staining did not change. The manufacturer’s label notes that it may add to the effect of blood thinners; people on blood thinners should check with their physician. Plain fish oil has not held up: the largest trial, DREAM, found it no better than an olive-oil placebo for symptoms or signs. These extras are not interchangeable, and all of them are information, not recommendations.
Where the idea stops
The hypothesis is strongest for the common chronic cluster. Limbal stem cell deficiency is usually caused by injury, burns, contact-lens trauma, or primary inflammation, though long-running surface damage may play a late part. Sjögren’s and other autoimmune diseases are their own processes; metabolism may modify them but does not explain them. A chalazion fits the picture of blocked, thickened oil; true eyelid and surface cancers are a separate matter with their own drivers.
The takeaway
Standard care manages the downstream signals well. The essay’s argument is that the bigger opportunity may be upstream: on this hypothesis the pillars come first so the glands are no longer starved, and the essay’s view is that extras come only after the pillars, if at all. Local measures still help break secondary cycles. Autoimmune disease, glands already lost to long blockage, injury, and medication damage are different problems and may still need conventional care. Responses vary from person to person. Talk with your own physician before changing any treatment.
A working hypothesis, open to correction and revised as new evidence arrives. Last revised October 17, 2026.
Related: Eye · Astaxanthin · NAD precursors · CoQ10 · Methylene Blue · Fewer Double Bonds · Fuel · Fuchs’ Dystrophy. Full version: the extended report, Ocular surface disease.
See the notice at the top of this page. Working hypothesis, not medical advice.