Ever notice your eyesight is different and wonder why? Vision changes can be due to a variety of reasons and should always be diagnosed by a qualified eye physician. But it’s also important to head into your appointment ready to talk about your medical history and any hormonal fluctuations you’re experiencing. Hormones can play a big role in your eyesight and your overall eye health.
The thyroid gland produces hormones that are essential to every part of the body. Thyroid hormones affect the cells of your eyes, including the cones responsible for color vision. It’s important not to have thyroid hormone levels that are too high or too low. Elevated levels of thyroid hormones are called hyperthyroidism. Hypothyroidism is the term used to refer to low levels.
In hyperthyroidism, the thyroid produces too much thyroid hormones. Most cases of overactive thyroid are autoimmune. The immune system mistakenly attacks the thyroid gland and creates inflammation. Hyperthyroidism caused by autoimmune issues is called Graves’ disease. In about 25% of people with Graves’ disease, thyroid eye disease also develops.
In Graves’ eye disease, the eyes and surrounding tissue can become inflamed. The eyelid muscles enlarge and the fat in the eye socket expands, which makes the eyes look like they are bulging out of the eye socket. Double vision, redness, dryness, and elevated eye pressure also occur. Sometimes, dry areas develop on the corneas due to the eyelids not fully closing, which can lead to ulcers or scarring. Swelling around the optic nerve can also cause vision issues or vision loss. Even though this rarely happens, quick diagnosis and treatment are important. Additionally, higher levels of T4, or thyroxine, put patients at an increased risk for age-related macular degeneration.
Hypothyroidism, or an underactive thyroid, can result in dry eyes, which usually feels like irritation or like there’s sand or grit in the eye. Patients with Hashimoto’s thyroiditis, or hypothyroidism caused by immune system dysfunction, can also experience thyroid eye disease. It’s generally more mild than what’s found with Graves’ disease.
Pregnancy and breastfeeding
During pregnancy, estrogen and progesterone levels are high. Water retention is most noticeable in the fingers, ankles, and feet. However, hormone fluctuations also cause fluid retention throughout the rest of the body, and the eyes are no exception. About one in six pregnant women report dealing with changes in eyesight, and these changes may last through breastfeeding. The buildup of fluid in the tissues of the eyes changes the shape of the cornea and increases pressure. Both can lead to blurry vision.
Anyone experiencing blurry vision or other vision changes while pregnant shouldn’t automatically brush it off. Bring it up with a healthcare professional. Blurred vision can be a sign of hypertension, or high blood pressure. Blurred vision can also be a sign of preeclampsia. (So can seeing flashing spots and sensitivity to light.) Preeclampsia requires immediate medical attention.
Perimenopause and menopause
Eye changes are common in perimenopause and menopause. Estrogen and progesterone fluctuate and ultimately decline. By menopause, levels of these hormones are low. These hormonal changes affect the cornea, which then affects the ability to focus up close. They also impact the eyes’ oil glands. Without as much natural lubrication created from tear film, the eyes feel dry. Dryness can be uncomfortable and leave long-time contact lens wearers suddenly reaching for glasses.
Many cases of mild dry eyes in perimenopause and beyond are treated with preservative-free artificial tears, or lubricating eye drops. Sometimes, in more severe cases, medications like Restasis are needed or even punctal plugs. Women with autoimmune conditions are most likely to need anti-inflammatory prescription drops. They are also more likely to develop dry eye.
Women on estrogen-only hormone replacement therapy may have a greater risk of dry eye compared to women not on HRT or on combination therapy.
Diabetes and PCOS
In diabetes, chronically elevated blood sugar can impact sight in a few ways. It can lead to changes in each of the cornea’s five layers. It can cause swelling of the lens inside the eye and can also damage the retina’s tiny blood vessels. When this happens, it’s called diabetic retinopathy. Diabetic retinopathy has four stages. Symptoms of later stages include vision changes, floaters, dark spots, retinal detachment, bleeding inside the eye, and even blindness.
Diabetes can also cause macular edema. The macula is part of the retina that provides our clearest vision. When fluid builds up around the macula, vision is affected.
Insulin resistance is a root hormonal imbalance behind PCOS. The hormone insulin is secreted from the pancreas. Insulin allows us to process and use sugar for energy. When not enough insulin is produced, or you can’t access the insulin you create, blood sugar levels remain unusually high (and can result in diabetes). High blood sugar can create swelling in the lens of the eye. (The lens is located behind your iris.) Swelling in the lens leads to fluctuating blurry vision.
Insulin resistance in PCOS raises insulin-like growth factor, or IGF-1 levels. Higher IGF-1 levels have the ability to change the eye structure, altering central corneal thickness. Increased central corneal thickness can lead to artificial elevation of the intraocular pressure when measured and cause mistaken diagnosis and treatment of ocular hypertension or open-angle glaucoma.
Reasons to check in with an ophthalmologist
Ophthalmologists are medical doctors or doctors of osteopathy. After medical school, another four years of extended training in surgery and diseases of the eye is required to practice in the specialty. While optometrists specialize in routine eye care, ophthalmologists are uniquely positioned to help with eye pain, physical changes to the eyes, perform surgery, and diagnose and treat any vision-related hormone issues and more.
The American Academy of Ophthalmology recommends a comprehensive eye examination (including dilation) every 2 years for those age 40–54, every 1–3 years for those 55–64, and every 1–2 years over the age of 65. If you have a personal or family history of eye disease, annual eye examinations are recommended as early diagnosis often means prolonged vision.
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