Headaches: Causes and Cures

Introduction

Headaches can strike at anyone, at any age, at any time. They are quite common; in fact, they are the most commonly cited reason for visiting a physician. Headaches are not only painful, they are the leading cause for absence for work or school, and contribute significantly to lost productivity.

Contrary to what most people believe, the pain of a headache is not in the brain tissue; the brain has no pain sensors. The pain of a headache comes from the blood vessels that nourish the brain, or from the tissues surrounding it.

Sometimes vision gets the blame for headaches, but usually the eyes are not the source of the pain. Occasionally, uncorrected or undercorrected hyperopia (farsightedness) or astigmatism may cause eyestrain and headaches, but most headaches are the result of other factors, such as tension, poor neck posture, sinus trouble, hormonal imbalance, high blood pressure, the aftereffects of alcohol use, or vascular constriction in migraines. Rarely, a headache may be from a serious cause such as a brain tumor or an aneurysm, but these are almost always accompanied by other symptoms.

Reading, using a computer or watching TV can bring on a headache if the activity puts strain on other body parts because of poor ergonomics. Ergonomics, the study of how body position and other factors can put stress on performance, may allow an analysis of how posture, lighting or the distance from the body to the work influences our comfort and performance.

One simple question can help clarify the situation: when does the headache appear? The answer will help the eyecare practitioner determine the cause of a headache. For example, a headache that is present when you wake up is almost certainly not visual in origin, but is more likely the result of a sinus condition or allergies. If the headache always comes on at a certain time of day, regardless of the activity at that time, it may be due to too much caffeine or a change in blood sugar level.

Other questions a physician may to help diagnose the cause of headaches include:

• What time of day does it come on?
• Does it happen every day, or just occasionally?
• Where on the head is it located? Does it move around?
• What do you do for it? Does that help?
• What are you doing when it occurs?
• How long does it last?
• How bad is the pain? (Most pain specialists have you rate the pain on a scale of zero to ten, zero being no pain at all, and ten being the absolute worst pain you’ve ever experienced.)

The answers to these and other questions should help narrow down the possible cause out of the many factors that could be at fault.

Visual Headaches

Some headaches actually are due to vision, and need to be addressed by an eyecare practitioner who can evaluate how the eyes focus and track objects in space, as well as diagnose any refractive problems like astigmatism, farsightedness or problems with convergence or divergence of the eyes when we are using them, particularly for near tasks like reading or computer use.

The visual system “wants” to be binocular; that is, it wants both eyes to be working together as a team. If an individual must compensate for uncorrected farsightedness, the muscles that do the focusing may be up to the task at first, but might have trouble keeping things clear over time. The focusing system is linked with the muscles that converge the eyes; a mismatch in the amount of focusing needed to keep the image clear and the convergence needed to keep it single, rather than double, can cause symptoms like a pulling sensation or forehead aches. Eventually, a mismatch such as this can lead to one eye turning inward or outward so the brain can suppress the vision so as to avoid double vision, especially over time. Binocularity is desirable, but the brain will over-ride that to eliminate double vision.

Vision problems such as these can cause symptoms like a “pulling” sensation in and around the eyes, a forehead achiness, or just an overall feeling of stress and tension.

Occasionally, people have different amounts of near- or farsightedness in one eye than in the other; if this difference is large enough, it can cause discomfort, either corrected or uncorrected. For example, farsightedness prescription lenses are convex in shape (the center of the lens is thicker than the edges) which magnify objects seen through them. If the amount of prescription power is different, one eye will see an image that is significantly larger than that seen by the other eye. To decrease this, it is sometimes necessary to reduce the difference in power in the final eyeglass prescription.

Also, an increase in pressure within the eye such as might happen during an episode of "angle-closure glaucoma" can cause headaches, particularly in the forehead area, along with halos around lights, blurred vision, or an eye-ache (as opposed to a headache). If the headache seems to occur mainly in darkness, as in a theatre or prolonged driving at night, there is a possibility it could be due to this type of glaucoma, "which is a vision-threatening emergency". If you think this may be the case, see an eyecare practitioner as soon as possible, for testing and treatment to avoid vision loss.

A headache that is visual in nature is usually relieved by resting the eyes and taking a mild pain reliever like that found in Tylenol or Advil. Visual headaches usually go away when the activity that stresses the vision is stopped.

Figuring it Out

While the underlying cause of a headache is not usually serious in itself, the pain certainly interferes in daily living and working.

It is always a good idea to have headaches checked on by an eyecare practitioner, even though many headaches are not visual in origin. If no underlying visual cause is found for the headaches and they persist or happen on a regular basis, see your primary-care physician to determine the cause. It should not be necessary for anyone to simply tolerate a condition when the cause may have a simple solution.

One of the best ways to help your doctor find the cause of headaches is a “headache diary” that records all the specifics: when you get them, where are they are on the head, what you are doing when they appear, how long they last, and anything else you think might be relevant.