Calcium in excess can cause several different problems in the eye, ranging from mild deposits within the eyelids to more severe problems like band keratopathy. On the other hand, too little calcium can also cause serious problems like papilledema, seizures, and heart failure.
The question is, why do these problems develop, and what can we do about them?
What Does Calcium Do for Our Bodies?
Calcium is a mineral found in dairy products—milk, cheese, yogurt, etc. as well as leafy green vegetables, and some white flour products.
Calcium cannot be made by the body and therefore must be consumed in our daily diet.
Calcium is used by the body for a variety of things. One of its most important functions is maintaining healthy bones—it is found in largest concentrations within the bones and teeth.
Calcium is also a very important player in many physiologic reactions. It is needed to help make muscles contract—including the heart! It is also responsible for helping to relay messages from nerves to the brain. Without calcium, our bodies’ “electrical grid” would go down and it would not be able to function properly!
Since calcium is not produced by the human body, it needs a little help from another vitamin in order for it to be absorbed by the system. This vitamin is Vitamin D—the vitamin commonly associated with sunlight exposure.
Therefore, it is essential to have proper levels of not only calcium, but also vitamin D. Having correct levels of one, but incorrect levels of the other would do us no good!
What is tricky about calcium is that levels have to be within a certain range in order to be beneficial—too much or too little can cause serious adverse effects.
Since calcium is such an important part of our overall health, the body has created a system to ensure there is always enough calcium, and even some calcium in reserve.
Calcium is important in young individuals for bone growth. As we get older, calcium is stored in the bones. There are a few organs in charge of regulating calcium release—the thyroid and the parathyroid glands, the kidneys, and the digestive tract.
The thyroid, parathyroid glands, and kidneys work together to detect the amount of calcium in the blood. If there is enough, they send a signal out telling the bones that calcium does not need to be released. If there is a shortage, they send a signal out telling the bones to release more calcium. This way calcium release is tightly controlled and used only as needed.
However, having so many different players in calcium regulation (calcium consumption, vitamin D consumption, bones, thyroid, parathyroid, kidneys, and digestive tract) leaves a lot of room for potential problems to arise and therefore affect calcium levels.
Problems Associated with Too Little Calcium in the Eye (Hypocalcemia)
Having a lack of calcium within the body can occur simply from having too little calcium or too little vitamin D in the diet, or it can be caused by a systemic disorder.
Some medical problems associated with hypocalcemia include hypothyroidism, hypoparathyroidism, cancers, and kidney disease.
But why do we care about Calcium in the eyes?
The eyes are a doctor’s gateway into the human body as the eyes are the only part of the body we can look into without requiring surgery. With a careful dilated fundus exam, eye doctors look at the retina and its blood vessels.
The health of blood vessels can tell eye doctors a lot about your overall systemic health.
In a person suffering from hypocalcemia, your eye doctor may see papilledema, optic neuritis, or early onset cataracts.
The exact physiology of why these findings occur is still being researched. However, eye doctors are educated on signs and symptoms of hypocalcemia and will be able to refer you for appropriate testing if one of these signs are seen within the eye.
Problems Associated with Too Much Calcium in the Eye (Hypercalcemia)
Hypercalcemia problems are a little more commonly seen than hypocalcemia problems.
Hypercalcemia occurs when there is too much calcium in the body. When the bones cannot hold any more calcium in storage or when vitamin D is not telling the bones to absorb calcium, calcium is left to float around throughout the body and deposit itself in random places.
This can occur due to a systemic disease such as hyperparathyroidism, cancer, tuberculosis, kidney failure, or sarcoidosis. However, it can also occur secondary to the aging process or from having extended periods of inactivity.
Thinking about the anatomy discussed earlier, remember that the bones store calcium, and vitamin D is needed to take the calcium we consume and absorb it into the bones for storage.
During extended periods of inactivity—think about someone who broke their leg and is sitting on the couch all day for a couple months—we are not using our muscles like we normally would. Therefore, we can have too much calcium floating around and the body needs to find a place to put it.
Similarly, hypercalcemia can also be seen as we age. As we get older, things start to hurt more than they used to. Many individuals are not quite as active as they used to be, and understandably so, it is hard!
However, if you are consuming more calcium than the body can store, or if you are not consuming enough vitamin D (remember we need vitamin D to absorb the calcium we eat), we can get excessive calcium in the blood.
One of the most common places for excess calcium to deposit itself in is the eye.
Calcium can ball up into little beads called concretions and sit in our inner eyelids. Most people are not bothered by these concretions, but if they get large enough they can irritate the eye. Think about a little hard pinpoint-size calcium ball stuck in your inner eyelid—it would be irritating!
Usually nothing is needed to be done about these findings. If you’re not irritated by them there really is no need to remove them. Many individuals have these and do not even know it! However, if you have one extremely annoying one, your local eye doctor will be able to remove it safely.
Another ocular finding that can be caused in part by hypercalcemia is a pinguecula. Most pingueculas are not caused by hypercalcemia, however, they are an area in which calcium can be deposited.
Pingueculas are areas of raised growths on the bulbar conjunctiva—a thin clear layer that covers the white part of the eyes.
Pingueculas often go unnoticed and are typically of very little concern. They are most often caused from sun exposure and will be seen in a majority of the population over time.
Pingueculas appear as a small, raised, yellowish area of growth. In some patients with hypercalcemia, calcium can deposit in these areas of growth and form a calcium nodule underneath the conjunctiva.
Like concretions, typically no treatment is necessary. If a calcemic pinguecula becomes irritating or a cosmetic concern, your eye doctor may refer you to an ophthalmologist to have it properly removed, however this is rarely necessary.
Now we will move on to findings of a little more concern—early cataracts and band keratopathy.
If hypercalcemia goes uncontrolled for an extended period of time, calcium can deposit itself onto the crystalline lens of the eye, ultimately causing a cataract to form.
Cataracts will form in essentially everyone as a part of the aging process. They typically do not become a major issue requiring surgical removal, however, until 60+ years of life.
In patients with hypercalcemia, however, cataracts can begin to form early in life—even within childhood years!
Hypercalcemic cataracts also tend to be a little faster progressing and denser cataracts than normal aging cataracts. Thus, they become more noticeable to the individual. A patient may begin to see a decrease in vision or note that their vision is cloudy. Other common complaints with cataracts are struggling with glare from overhead lights.
Hypercalcemic cataracts will require surgery. Cataract surgery is a simple process in which the natural lens of the eye is removed and replaced by an artificial one.
Band keratopathy is another more slightly concerning finding. Band keratopathy results in deposition of calcium across the very front clear structure of the eye called the cornea.
Typically band keratopathy starts at the outer edges of the cornea, the 3 and 9 o’clock positions.
In the early stages, band keratopathy does not really affect your vision. It is the later stages when the two side edges grow inward to connect at the middle (like a band across the eye) that it becomes a problem.
When band keratopathy covers the entire cornea, it can make it very difficult to see—it would be similar to looking through a dirty fish tank.
Luckily, band keratopathy does not always progress to this more advanced stage. Many cases do not require any treatment at all!
However, if band keratopathy does progress to cover the cornea, treatment is as simple as using prescription eyedrops to clear up the deposits.
To sum up hypercalcemia, the best treatment is to find out why your blood calcium levels are elevated and get that under control as hypercalcemia (and hypocalcemia) can have very serious systemic complications. Eye findings are typically minor and have simple treatments to reduce irritation and get you back to normal.
The best thing you can do is to see your eye doctor yearly. Eye doctors can detect a plethora of problems—including issues with calcium levels. While most cases of hypocalcemia and hypercalcemia are not of major concern, every now and again a more serious issue can be detected through an annual eye exam. You eye doctor can get you proper referrals and the needed treatment ASAP to potentially save your life!
