I have a lot of conversations about birth control. It’s what I do. I’m kind of a one trick pony that way. Anytime you engage in a similar discussion with a variety of people, you begin to see patterns in how they respond.
The first pattern that pleasantly surprised me was that a vast majority of women enthusiastically welcome the voice of a concerned man in their conversations about the dangers of birth control, even among women who haven’t necessarily embraced the idea that birth control carries unnecessary risks. However, as a sort of soft rebuttal, I have heard this response more than a few times: “I’ve been taking birth control for x-number of years, and it hasn’t affected me.”
I wrote in my book and in a few articles since, that this statement saddens me because it leads me to think about how this woman’s story has yet to be fully written. Sure, maybe she hasn’t experienced any of the immediate complications we think of that injure or kill women – like strokes, blood clots, DVT, or pulmonary emboli, but birth control is the gift that keeps on giving.
There’s still time for her to develop a liver adenoma or maybe an autoimmune disease like lupus, multiple sclerosis, or Crohn’s disease – and further down the road, breast cancer, skin cancer, or gallstones. There’s a good chance whenever she develops any of these conditions she won’t even realize it could have been caused by taking these potent steroids.
Heck, I’ve spent years researching birth control, and I’m still finding connections I never knew existed.
The Eyes Have It
I recently attended a meeting of glaucoma specialists discussing diagnosis and treatment of the disease. I’m not a medical professional, but as they spoke, I happened to recognize a couple of the biomarkers they mentioned. It made me wonder whether hormonal birth control might contribute to an increased risk of glaucoma later in life.
I pulled out my phone and turned to my trusted friend, Google Scholar. Sure enough, a large population-based study released in 2013 incorporated a multivariate analysis of nearly 3,500 women over the age of 40 and found that those who had used hormonal birth control for three years or longer more than doubled their risk of developing glaucoma.
That’s significant and alarming. However, when we’re younger, over-40 sounds so far away and it’s easy to convince ourselves it won’t happen to us. That’s human nature. If it wasn’t, literally nobody would still be smoking.
A Deeper Look
Let’s look at what might cause this dramatic surge in glaucoma patients among women who took birth control. At first, the research makes this entire concept seem counterintuitive.
A few studies over the past 25 years demonstrated that postmenopausal women taking hormone replacement therapy actually saw an improvement in their intraocular pressure. High intraocular pressure is the key factor in most glaucoma patients.
If the synthetic steroids in hormone replacement therapy for menopausal women benefit intraocular pressure, the assumption might be that similar synthetic sex hormones in birth control during the reproductive years should also be beneficial.
Digging deeper, we find that a 2012 study demonstrated that estrogen deficiency accelerates aging of the optic nerve. Okay, so it still makes sense that a chemical that mimics natural estrogen might offer relief to postmenopausal women whose bodies have drastically reduced natural estrogen production, but what about younger women on birth control?
Actually, that question is what made the 2013 study so fascinating. Rather than a protective effect, researchers found that women who had taken birth control were at a much greater risk of developing glaucoma and consequently had higher intraocular pressure.
Is It Really Counterintuitive?
The first study that sheds some light on what might trigger this negative effect dates back to 1975. It revealed that hormonal birth control effectively shuts down a woman’s natural cycle. With The Pill, their synthetic ‘estrogen’ levels remained constant throughout the month, rather than the ebb and flow of natural hormones that accompany the various phases of their cycle when birth control isn’t present.
In a recent plea for ‘pharmacovigilance’ published in the Journal of Pharmacology & Pharmacotherapeutics, doctors theorized that birth control’s flattened curve of estrogens could be responsible for this threat to the eye. The destruction of the natural peaks and troughs of estrogen throughout the cycle leaves the woman’s body in a virtual state of estrogen-deficiency.
While a woman takes the drug, the flattened curve may create a ‘virtual’ estrogen-deficiency, but by shutting down her natural estrogen production, when she stops taking birth control, she faces a very real estrogen-deficiency. Consequently, hormonal birth control poses a dual-pronged threat. The depletion of natural estrogen exposes her to premature aging of the optic nerve and higher intraocular pressure, both of which could contribute to a future glaucoma diagnosis.
Not So Distant Future
Perhaps the most sobering thing to remember is that glaucoma is not just an old person’s disease.
A 2021 study of over 4.8 million subjects found that women currently using hormonal birth control, which included modern delivery methods like rings, inserts, and IUDs, were more than twice as likely to be diagnosed with glaucoma – today, right now, not later in life.
While the relative risk of developing glaucoma during the reproductive years remains pretty low, we can now include glaucoma among the diseases that we think of as an old person’s disease, which is being skewed younger thanks to these potent drugs.
Removing the Blinders
But, concern for how hormonal contraceptives affect the eyes doesn’t end with glaucoma. I decided to extend my search to see if scientists had discovered any other complications. In fact, recent years have seen a growing unease among ophthalmologists regarding the overall impact these steroids may be having on women’s eyes.
A recent study looked at how this drug affects the thickness of the macula, retinal nerve fiber layer, ganglion cell layer, and choroid. The researchers found that, after only one year, women on birth control experienced a significant change to their retinal and choroidal thickness, which could affect their central vision.
In discussing their findings, the researchers suggested that women taking hormonal birth control should have regular OCT imaging done on their eyes and stated:
It is important to find out when these thickness alterations can be clinically significant or symptomatic and if these changes are reversible or not.
It Doesn’t End There
In a way, none of these findings should be surprising. I’ve written extensively about how the steroids in birth control affect nearly every system of the body because of how ubiquitous hormone receptors are on the various cells throughout our body.
But for those us who don’t spend a lot of time contemplating the eyeball, it can be easy to overlook the fact that our eyes also have a complex vascular system.
Again, The Pill’s contribution to blood clots, strokes, and heart attacks has been pretty well documented on this website and in my book. So, is it possible the drug could cause a similar effect in the eyes?
The most common disease of the retina, which causes severe vision loss, is known as Retinal Vascular Occlusion (RVO), essentially the blockage of a blood vessel in the retina. It usually occurs in middle-aged and older people. However, a study from 1997 showed that of the female patients under 35 years old with RVO, 66% were taking hormonal birth control.
A follow-up study in 2013 affirmed the previous study’s correlation, stating that apart from hypertension, diabetes, advancing age, or genetic predisposition, hormonal birth control is the most common predisposing factor for RVO.
The authors pointed out that doctors now commonly prescribe birth control off-label to treat ovarian cysts, ‘regulate periods’ in PCOS or puberty, and down-regulate IVF cycles. With this increase in prescriptions, they warned:
The risk for retinal vascular catastrophes is also rising.
This isn’t just a theoretical concern in the labs. Some leading ophthalmic practices now list oral contraceptives as a risk factor for RVO alongside obesity and smoking.
Seeing the Light
I ran this article past a friend, Dr. Anne Malatt, an eye surgeon, and asked her for any thoughts or feedback. Here’s what she wrote:
I am amazed that as an eye specialist who is also a woman, mother and grandmother, I have not previously heard of any association between the contraceptive pill and eye disease, and particularly nothing about glaucoma. This is important information to share with everyone, including eye specialists and we should now be asking all the women we see as patients about any history of taking the pill. We currently screen everyone over the age of 40 for glaucoma, but in light of these findings, we should be considering screening all adult women who are taking or have taken hormonal birth control, for both glaucoma and retinal disease. And it would be wise to consider alternative modes of family planning, rather than taking these powerful and potentially harmful medications.
It’s wonderful that ophthalmologists and optometrists are taking note of birth control’s role in eye disease. Unfortunately, they aren’t the ones prescribing hormonal contraceptives. Do you think any ObGyn, primary care physician, or Planned Parenthood clinic tells women they need to schedule routine OCT imaging to monitor changes in their eyes?
Neither do I.
Hopefully, the word will spread to those doctors soon enough and they too will see the light.
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