Recently I had a patient visit my office with a very frightening visual experience. Earlier that day while drinking coffee, he noticed that he lost close to 95 percent of his vision in his one eye. After three minutes, the vision in that eye returned to normal. He reported no other unusual symptoms.
Most of us would agree that experiencing any temporary visual loss would cause us to be concerned. Obviously it is not normal to lose vision, even temporarily. There are several possibilities to explain what occurred with this patient. The most common cause of temporary vision loss is a transient ischemic attack. It is more commonly known as a TIA or a “mini-stroke”.
TIAs are a warning sign that a stroke may occur. They are caused by a reduction in blood flow to the brain or eye for a short period of time due to a small blood clot. Symptoms of a TIA may include one or more of the following: painless loss of vision of one or both eyes, weakness and tingling on one side of the body, difficulty speaking, or vertigo (dizziness). When the blood flow returns, usually in a matter of minutes, the symptoms go away. Rarely does a TIA last for more than twenty four hours. With a stroke the blood flow does not return causing permanent damage.
The risk factors of transient ischemic attacks are as follows: high blood pressure, high cholesterol, smoking, IV drug use, cocaine use, excessive alcohol, use of oral contraceptives, and lack of exercise causing obesity.
Patients suffering from a transient ischemic attack need to see a doctor as soon as possible. A list of tests the doctor may order include blood pressure, full blood work-up, CT scan, MRI, Doppler ultrasound, or an echocardiogram. If a loss of vision is experienced, an examination by your optometrist or ophthalmologist is important to rule out any other possible causes of vision loss.
Initial treatment of a transient ischemic attack usually involves taking blood thinners. The long-term treatment of a TIA depends on the cause of the attack.
The symptoms of a transient ischemic attack may only last a matter of minutes but they should not be ignored since roughly fifteen percent of patients who survive their first TIA or stroke will suffer another one within one year.