# Myopia

Category: Conditions

Also known as: nearsightedness, shortsightedness

Myopia is fundamentally a symptom of hypothyroidism and a chronic deficiency of glucose supply to the eye, a connection Ray Peat began drawing from his own childhood observations. Peat noted that the onset of nearsightedness often begins in puberty, particularly in girls, as a…

9 passages · 1 author · 1993–2021 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

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## Synthesis

**Myopia** is fundamentally a symptom of **hypothyroidism** and a chronic deficiency of glucose supply to the eye, a connection Ray Peat began drawing from his own childhood observations. [Source 1, 7] Peat noted that the onset of nearsightedness often begins in puberty, particularly in girls, as a result of low thyroid function, and he witnessed cases where timely thyroid supplementation corrected vision to normal. [Source 1, 8] He argued that the eyeball elongates because the smooth muscle cells in its wall, responsible for maintaining its roundness against the near-focus apparatus, are chronically starved of glucose. [Source 7] This starvation is exacerbated by estrogen, which lowers blood sugar, explaining why many young women rapidly become myopic within weeks of starting the oral contraceptive pill, and why their vision can return to normal upon stopping the pill or beginning thyroid therapy. [Source 2, 7]

The biochemical environment of the eye's connective tissues is central to the pathology. Peat explained that the sclera and cornea are rich in *mucopolysaccharides*, and that hypothyroidism leads to a condition of "myxedema," where tissues become overloaded with these glycoproteins, causing swelling and softening. [Source 2, 6] He identified **high prolactin**, associated with high estrogen or low thyroid, as a likely factor in this process, since several pituitary hormones stimulate mucin overproduction. [Source 2] In experimental models, keeping animals in darkness or covering their eyes causes the eyeball to grow larger than normal, producing a soft and weak sclera. [Source 2, 6] Peat theorized that darkness mimics hypothyroidism by reducing nerve stimulation, which normally consumes oxygen and emits **carbon dioxide**, thereby allowing the connective tissues to swell. [Source 6]

Peat placed **carbon dioxide** at the center of both the problem and the solution, linking it directly to the anti-swelling and structural integrity of the eye. He reasoned that carbon dioxide maintains the fluidity of the aqueous humor and prevents edematous swelling in the cornea and lens, whereas in hypothyroidism, *lactic acid* is substituted for carbon dioxide, increasing viscosity and potentially contributing to glaucoma. [Source 2] The therapeutic effect of high altitude on myopia—where Peat himself experienced a 3-diopter improvement—is explained by the *Haldane-Bohr effect*: reduced oxygen pressure causes hemoglobin to retain more carbon dioxide, creating the same tissue condition that optimal thyroid function does. [Source 4, 8] He also suggested that carbon dioxide saturates amino groups on structural proteins, inhibiting the chemical cross-linking that hardens connective tissue in aging. [Source 6]

The role of **serotonin** provides another mechanistic layer. Peat cited research showing that animals kept in darkness or with blurring lenses become nearsighted as the eyeball grows longer under the influence of increased serotonin, and that serotonin antagonists protect against this experimental myopia. [Source 3] He connected this to the higher incidence of myopia and migraines in females, noting that estrogen inhibits the monoamine oxidase-A enzyme that detoxifies serotonin, while progesterone activates it. [Source 3] An antithyroid effect from substances like excess dietary iodine can also manifest as nearsightedness. [Source 9] Peat's recommended interventions included anti-estrogen and anti-stress nutrients, adequate light exposure, and thyroid supplementation to restore the anabolic, carbon dioxide-rich metabolic state that maintains the eye's normal shape. [Source 5, 7]

## People also ask

### How does hypothyroidism cause the eyeball to elongate in myopia?

Peat argued that low thyroid function starves the eye's smooth muscle cells of glucose, weakening their ability to maintain roundness, while also causing a myxedematous swelling of the sclera from mucopolysaccharide overload, which together allow the eyeball to stretch.

### Why can stopping the birth control pill improve nearsightedness?

Peat observed that the estrogen in oral contraceptives lowers blood sugar, exacerbating the glucose starvation of the eye's structural muscles, and that discontinuing the pill or starting thyroid therapy can restore normal vision by correcting this metabolic deficit.

### What role does carbon dioxide play in maintaining proper eye shape?

Peat explained that carbon dioxide prevents edematous swelling in the eye's connective tissues and maintains fluidity in the aqueous humor, whereas in hypothyroidism it is replaced by lactic acid, leading to softening and deformation of the eyeball.

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## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — Thyroid, Hypothyroidism & Diet, Lifestyle, Exercise to Fix it!

Ray Peat · Interview · Jul 20, 2019 · https://www.youtube.com/watch?v=HNTgD6djJtE

> **Jodelle Fitzwater:** Right, so that's why you hear doctors saying now, eat less, move more, that's their prescription now when we see these people with thyroid issues.
>
> **Ray Peat:** stay obese despite saying that they ate almost nothing doctors doctors were taught that women were basically lying about how much they ate but but someone did the study had women in a locked hospital ward where there's no possibility of getting extra food and it was found that these women who said they ate almost nothing but gained weight, they were found to be able to maintain their weight on a diet of 700 calories a day. The only way to do that is to be very hypothyroid. But it's still very common for extremely hypothyroid women in particular to be diagnosed as gluttonous rather than hypothyroid. Well, let's talk about some of the major symptoms that someone would see if they suspect they might have low thyroid. What are some of the major signs they would notice and see clearly with their own body? When I was 9 or 10 years old, I started noticing symptoms in myself that I saw that more girls had similar symptoms I didn't see any other boys with migraine headaches and nearsightedness but these often begin in puberty as a result of low thyroid and I've known girls in their teens who had just suddenly become nearsighted and when a doctor gave them a thyroid in a timely manner, their vision was corrected to normal. So chronic myopia is one of the very frequent signs of hypothyroidism. Weight loss, inability to gain weight, was known more than 100 years ago. 1890, the first publication relating the wasting disease. They called it tachyxia streumetriva caused by loss of the thyroid function. So overweight or underweight both can be caused by low thyroid. The thyroid hormone is an anabolic hormone that builds protein tissues and bones. But doctors by getting most things upside down, doctors warn that excess thyroid will cause osteoporosis.

### Source 2 — Tissue Firmness and Elasticity, and Rothen's Resonance

Ray Peat · Article · 1998

> The transparent structures of the eye are interesting places for considering the effects of carbon dioxide. I think carbon dioxide has a role in maintaining the clarity of the lens, as I discussed in the cataracts newsletter, by preventing swelling. The connective tissues of the eye's sclera and cornea are rich in mucopolysaccharides, and the vitreous body and the aqueous humor are very much like more dilute solutions of the same materials—the cornea is the most dense, and the aqueous is the most dilute. The fluidity of the aqueous is important because it circulates nutrients and oxygen from the blood, to sustain the lens and the cornea. The individual molecules in the aqueous are larger than those in the vitreous, but because there are fewer of them, the aqueous isn't very viscous. If carbon dioxide affects these molecules as it does the mucins in the bronchial secretions, then we can infer that it is important in maintaining the fluidity of the aqueous humor; this would suggest that hypothyroidism, leading to a substitution of lactic acid for carbon dioxide, might contribute to the development of glaucoma by increasing the viscosity of the aqueous humor.
>
> Among mountain climbers, it has been reported that after staying several hours at a very high altitude, there is a decrease in the degree of myopia. Because of the Haldane-Bohr effect, in which carbon dioxide is retained when less oxygen is available, I think the high altitude effect on myopia involves a condensation of the connective tissue. In experimenters wearing gas-tight goggles, and in scraped corneas kept in tissue culture, carbon dioxide has been found to have an anti-swelling effect on the cornea.
>
> When rats have their thyroid glands removed, they become nearsighted, but if their pituitary glands are removed at the same time, they don't develop myopia. Hypothyroidism is classically associated with "myxedema," in which the tissues become overloaded with the glycoproteins or mucins. Several pituitary hormones are known to stimulate the overproduction of mucins. In several of my classes, I asked students if they remembered when they became nearsighted.

### Source 3 — Serotonin: Effects in disease, aging and inflammation

Ray Peat · Article · 2015 · https://raypeat.com/articles/articles/serotonin-disease-aging-inflammation.shtml

> The latter experiment shows that everyone's perception involves an outward-directed activity of the brain, and the experiments using the chemical stimulants suggested that the intensity of the outward-directed action can vary.
>
> The inhibitory serotonergic "harm avoidance" system, and the opposing excitatory activating "novelty seeking" systems are constantly being influenced by many factors, including nutrition, hormones, environmental challenges and opportunities, social interactions, seasons, and the rhythm of night and day alternation.
>
> Several kinds of research are now showing that the effects of the environment on the serotonergic system and its antagonists can influence every aspect of health, not just the personality.
>
> For example, there have been suggestions that early life isolation of an animal can affect its serotonergic activity and increase its anxiety, aggression, or susceptibility to stress (Malick and Barnett, 1976, Malick, 1979, dos Santos, et al., 2010), and these effects are associated with increased risk of becoming depressed, and developing organic problems. Animals kept in darkness (or with blurring lenses) become nearsighted, as the eyeball grows longer under the influence of increased serotonin, and the eyes are protected against myopia by serotonin antagonists (George, et al., 2005). The incidence of myopia is increasing, at least in countries with industrialized economies, and is more common in females.
>
> Migraine headaches are also increasing in incidence. By the end of the 1950s, it was widely accepted that migraine headaches and associated symptoms including nausea and visual disturbances were caused by an excess of serotonin, and antiserotonin drugs of various types were being used for treatment. In one of the early studies of the use of LSD in psychotherapy, some of the patients noticed that their chronic headaches had stopped. Cluster headaches have also responded well to LSD and similar drugs (Sewell, et al., 2006).
>
> Women have migraines more often than men do, and they tend to occur in association with ovulation or menstruation. Estrogen inhibits monoamino oxidase, MAO, especially the A form that is most active in detoxifying serotonin, and it increases the enzymes that control the rate of serotonin synthesis. During serotonin excess, the veins and capillaries of the pia mater are engorged with blood, while circulation to the brain generally is depressed.

### Source 4 — Ray Peat Email Advice Depository — Post 364

Ray Peat · Email · Apr 28, 2017

> **Question:** [2011] [Myopia / Nearsightedness]
>
> **Ray Peat:** My myopia improved about 3 diopters when I spent a few months at high altitude, and took some pregnenolone . I think it's the CO2 balance in the tissues with reduced oxygen pressure, Bohr effect. If you are adapted, the higher altitudes have more effect. The time I noticed the biggest change I was only at 6600 feet altitude, but shorter stays at 8700 feet caused quick improvement. I used that method for several years and stopped the progression while I did it, but when I started to read all day year after year, I neglected it. I got it from Aldous Huxley's Art of Seeing, describing the Bates method. I worked with an optometrist who had studied at Ohio State, when their optometry school was progressive.

### Source 5 — Nutrition for Women

Ray Peat · Book · 1993

> If smooth muscles in the wall of the eyeball are responsible for maintaining the roundness of the eye, against the near-focus apparatus around the lens, then chronic starvation of those cells would lead to elongation of the eyeball (in proportion to the amount of close work), producing myopia. Besides avoiding the pill, all of the anti-estrogen and anti-stress nutrients should help to prevent the progression of myopia, and being outside in good weather — to promote the tear flow — might even reverse it, as thyroid hormone does.
>
> ### Colitis, Regional Enteritis (Crohn's Disease), Inflammation, and Fibrous Diseases, and "Collagen Disease"
>
> Stress consumes steroids and produces the many degenerative diseases described by Hans Selye. The gastro-intestinal system becomes inflamed or ulcerated, and fibrous tissue may proliferate. Adrenal glands enlarge, and lymphoid tissue shrinks during the first stage of stress (and may enlarge later). Stress can be produced by dark cloudy northern winters, by inadequate nutrition, by the use of estrogen and many other drugs, and by the use of foods which inhibit the thyroid gland (bakery bread, lacking available manganese and containing iodate and bromate; cabbage family, and many cereals and nuts containing nitriles, cyanide or thiocyanate; meats "refined" from animals whose thyroid tissue is sold to drug companies). Stress diseases typically have a dominant allergic aspect, and respond to steroids. Cortisone is used medically, but has side effects which could be avoided by using progesterone (though "medical" progesterone usually contains allergenic solvents and "preservatives" such as phenol). Niacin, vitamin A, vitamin C, etc., help to produce progesterone, and so often help in stress diseases, though the manufactured substances are themselves somewhat allergenic. (Vitamin A is not usually "manufactured.") Light deprivation can be remedied artificially, but the necessary brightness is usually underestimated. Because an adequate diet is hard to get in our culture, which makes it illegal to sell the thyroid gland as food, it is often necessary to buy this powdered meat in tablet form from your physician and druggist. Meat eaters would normally get 1/4 to 1/2 grain of thyroid in their food every day if the whole animal were used.

### Source 6 — Tissue Firmness and Elasticity, and Rothen's Resonance

Ray Peat · Article · 1998

> Several pituitary hormones are known to stimulate the overproduction of mucins. In several of my classes, I asked students if they remembered when they became nearsighted. Although puberty is the usual time for myopia to begin, several girls mentioned that they had needed glasses within a month of beginning the oral contraceptive pill, and some of them found that their vision returned to normal when they stopped the pill, or began using thyroid supplements. High prolactin (associated with high estrogen or low thyroid) may be one of the factors in myopia.
>
> Another experimental method for producing myopia is to cover the eye of a growing animal, or to keep the animal in constant darkness. In darkness, the eye grows larger than normal, causing the refractive error of myopia, and the sclera is soft and weak. Since stimulated nerves consume oxygen and emit carbon dioxide, I think darkness might mimic hypothyroidism, allowing the connective tissues to swell.
>
> The sea cucumber has been used to study the physical properties of connective tissue, and it has been found that certain salts tend to soften the connective tissues, but that iodide doesn't. The well-established use of iodide to resolve granulomas, even when it doesn't eliminate the infectious agent, might suggest that it is protecting against something which is disrupting the connective tissue structure. The only publications I have seen that presented clear evidence of the disappearance of arteriosclerosis involved treatment with iodides. In the retina, blood vessels can be seen to return to their normal appearance following a course of iodide treatment. Besides its possible direct effects on the mucins, iodide might help to eliminate calcium from the walls of blood vessels, since calcium iodide is very soluble.
>
> In aging, connective tissue becomes hardened by chemical cross-linking of the large molecules. If amino groups are well saturated with carbon dioxide, this type of reaction should be inhibited. (Carbon dioxide also inhibits the production of free radicals, which are involved in some types of cross-linking reactions.) The waterlogged condition seen during shock or stress in blood vessels, lungs, and other organs, and the edema of the brain and cataracts of the lenses that follow metabolic impairments of various sorts, seem to involve the uptake of "free" water, at the same time that "bound" (unfreezable) water is lost.

### Source 7 — Nutrition for Women

Ray Peat · Book · 1993

> Other vitamins that can improve circulation by opening the small blood vessels are folic acid and niacin. Vitamin C can help to eliminate toxins that could contribute to high blood pressure. Trace minerals (such as those found in kelp and bran) and magnesium should also be considered in circulatory problems. Magnesium acts against calcium (and estrogen) in the clotting system, can prevent spasms of blood vessels, and can spare oxygen. According to Barnes, nearly all hypertension can be helped with thyroid.
>
> ## IV. Some Diseases
>
> ### Nearsightedness (Myopia)
>
> Many years ago I noticed that my nearsightedness increased when I was under stress. Many people become slightly nearsighted at night, or in the dark. Since the blood sugar concentration decreases at night, and under certain stress conditions, I guessed that myopia might be caused by chronic deficiency of sugar supply to the eye. This idea was reinforced when I read that tears normally contain more glucose than do the other body fluids, and then found that my tears usually had less sugar than the eyes of people with normal vision or with farsightedness. I found that many people (not just diabetic, whose altered refraction is usually blamed on swelling of the eyeball) had experienced very rapid and large changes in their degree of nearsightedness. In young women, I found that it was very common for them to become myopic within weeks of the time they began taking birth control pills, and that their vision sometimes corrected itself when they stopped taking the pill after a year or two. In women who were on the pill, and then began taking thyroid hormone, the thyroxin tended to correct their vision. Since estrogen tends to lower the blood sugar level, and thyroxin tends to raise it, these observations are consistent with the idea that myopia is caused by a deficiency of glucose in the eye. In the walls of the eyes of chickens, cells which look like smooth muscle cells are present. If smooth muscles in the wall of the eyeball are responsible for maintaining the roundness of the eye, against the near-focus apparatus around the lens, then chronic starvation of those cells would lead to elongation of the eyeball (in proportion to the amount of close work), producing myopia.

### Source 8 — 2020.06.10 | Dr Ray Peat Q&A - Weight Loss, Stretch Marks, Hydrogen, Negative Ions and More!

Ray Peat · Interview · Jun 10, 2020

> **Jodelle Fitzwater:** Oh, that is so cool, because since improving my thyroid, and eating less PUFA and stuff like that, after years of researching this stuff… My diopter went from -6.75 down to -5, so it's slowly improving. I don't think people realize that you can actually reverse vision problems.
>
> **Ray Peat:** Yeah. I've seen that happen in girls at puberty or mid teen years. It's very common for a girl to experience sudden onset of myopia. If they get their thyroid corrected around the same time, they no longer have myopia, so it's prolonged hypothyroidism that causes progressive myopia. The connection between high altitude and thyroid is that thyroid is what lets your mitochondria produce carbon dioxide and keep the inflammatory lactate as suppressed, and at high altitude the simple physics of the Bohr/Haldane effect on hemoglobin… The reduced air pressure causes your hemoglobin to retain a higher level of carbon dioxide, and so it's creating the same condition in your body that optimal thyroid function does.
>
> **Jodelle Fitzwater:** Awesome! Re. molecular hydrogen: “I've seen a lot in the online stores with molecular hydrogen tablets and how they improve hydration. What are your thoughts?”

### Source 9 — One Radio Network: Ray Peat with Patrick Timpone — December 20, 2021

Ray Peat · Interview · Dec 20, 2021

> **Ray Peat:** An antithyroid effect can show up as nearsightedness.
>
> **Patrick Timpone:** Wow, interesting. Final one. This is a good question. Oh, somebody just wrote in here. Oh, our friend Adam Bergstrom, Dr. Peat. He said Guy E. Abraham.
>
> **Ray Peat:** Yeah. I'm not sure how you pronounce his first name. French would be Guy.
>
> **Patrick Timpone:** Guy E. Abraham. That's who you're talking about on this iodine thing.
>
> **Ray Peat:** Yeah.
>
> **Patrick Timpone:** Wow. Final one. So Dr. Peat just said that the thyroid has to do a lot with hair follicles and calling it a low-thyroid TSH reading. Would increasing my dosage help with the hair falling out as I am on two-grain natural thyroid? And would it raise my heart rate if I increased it? So she's right now on two grains, which is, what, 120 milligrams?
>
> **Ray Peat:** Yeah, that was the average dose for decades
>
> **Patrick Timpone:** using farmer's thyroid. And would that, do you think the average dose is higher now for any reason?
>
> **Ray Peat:** No, it's probably around 120.
>
> **Patrick Timpone:** And again, if somebody wasn't sure, they can either do the test or work with the body temperature and the pulse.

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