Understanding Headaches that Cause Visual Disturbances
Headaches are never pleasant, but they are very helpful warning signs. At the very least, they are a signal that a patient may need to start or stop doing something fundamentally different in life, such as to start eating breakfast, start wearing reading glasses, start getting more sleep, stop drinking so much coffee, stop smoking, or stop getting into so many stressful situations. If a patient does not respond to these headaches, they probably develop more severe physical problems in the future. But headaches can also mean something terribly ominous, something that must be evaluated immediately. Usually, these headaches do not go away completely, but rather get worse (but not always!). In addition, these headaches are often accompanied by signs and symptoms relating to the eyes.
Why do Headaches Hurt?
The brain never will feel pain! This is because there are no nerve fibers of the type that transmit pain signals located within the brain substance. In fact, neurosurgeons routinely operate on patients under regional anesthesia while the patients are awake and able to speak. Pain in the head comes from signals originating in the bone, the eyes, the sheathes surrounding the brain (called the meninges), and the blood vessels. Headache is generally caused by an inflammation or pressure on these structures and the physician will make use of the patient's description of the quality (i.e., pressure, throbbing, tightness, burning, etc.) and location (over or behind the eyes, near the nape of the neck, the temples, etc.) of the headache to help pinpoint the problem.
Why would a Headache Affect Vision?
Approximately 70% to 90% of the brain is involved in either seeing, interpreting visual information, or controlling the muscles of the eye. It should be no surprise that disease in the head would somehow affect one's vision. In addition, the eyes, when sick, will often hurt, and therefore cause pain in the head. This is why patients suffering with chronic headaches should always see an ophthalmologist. An ophthalmologist is a doctor with special training in the ways that the eye and brain interact, as well as in ways systemic and cranial disease can affect the eyes. Ophthalmologists are frequently consulted in patients who suffer chronic headaches, especially those patients who suffer visual changes or disturbances along with the pain.
What Visual Disturbances are Associated with Headache?
As any migraine sufferer might tell you, headaches can be accompanied by virtually any visual disturbance. Migraines, for example, are often preceded by flashing lights or by deficits in the visual field so that a patient might describe "everything to the left becoming dark". In addition, once the migraine has commenced, the patient will often note severe irritation and pain from bright lights (or photophobia).
Patients with serious and perhaps life-threatening diseases of the main arteries bringing blood to the head, the carotid arteries, may notice shooting pain from their neck to their head associated with the eye on the affected side seeing poorly at distance (while seeing better for reading) and having a small pupil and somewhat droopy eyelid. Patients with increased fluid pressure in the brain may notice that they are seeing double, or a friend may tell them that one of their eyes is turned out. These patients will often suffer severe headaches and maybe even nausea or vomiting.
Patients with aneurysms, (abnormal bulges in their cranial blood vessels), will often experience severe headache as well as an inability to see up close with one eye (although the same eye may see normally at distance!), double vision, and a larger pupil in the affected eye. Patients with brain tumors may notice headache associated with a slowly progressive loss of vision, often from one eye and then the other, while elderly patients with an inflammatory disease called Temporal Arteritis (or Giant Cell Arteritis) may notice severe pain in the temples and sudden visual loss.
Patients with meningitis, infectious inflammation of the meninges, may notice blurred or double vision as well as severe headache and especially neck pain. Therefore, headaches associated with visual disturbances of any kind can be quite deadly or lead to catastrophic visual loss. This information is presented not to frighten patients but to remind them that a headache is a warning sign and the body's way of telling a patient that some intervention is needed while there is still enough time to seek help.
How does an Ophthalmologist Diagnose Headaches?
The "wiring" in the brain is becoming better understood all the time. Ophthalmologists use their understanding of these connections to localize the source of a headache. For example, a patient complaining of headache associated with unilateral pupillary dilation, double vision, and an inability to move the affected eye any way but to the side clearly raises the likelihood of an aneurysm in the blood vessel called the Posterior Communicating Artery. This diagnosis will permit the ophthalmologist to immediately arrange emergent surgical intervention so that the aneurysm can be treated before it bursts, a potentially fatal occurrence. Notably, a routine CAT scan or MRI of the brain might not detect this lesion! The best imaging technology available today still cannot pinpoint a lesion as well as a thorough physical examination and history of the patient's illness, and these advanced tests are used more appropriately to corroborate the clinician's findings. Concerning that aneurysm, the ophthalmologist would know to order a special test called angiography, that highlights only the blood vessels, thereby permitting detection of the sick artery. Sometimes, the cause of a headache is not so clear; in these cases, the ophthalmologist will help the patient map out their headaches by instructing the patient to keep a headache diary. Often, triggers for the headaches will become obvious within a few weeks. Ultimately, the cause of most headaches can be discovered, and the ophthalmologist will work closely with the patient and other members of the patient's health care team to formulate an effective and safe treatment plan for the headache sufferer.