Seeing spots or flashes of light or experiencing blurry vision in general are all common complaints after physical activity. In fact, many refer to these spots and colors as "seeing stars." Such vision issues are caused by a variety of factors that are easily fixed. However, if you experience ongoing vision problems, or if seeing spots and colors is accompanied by additional, ongoing side effects, consult a physician immediately.
During and after a workout, blood is often pumped away from the brain and eye muscles. This causes an array of strange vision side effects, such as flashes of white light, blurriness and splotchy colors. If you experience this while working out, stop momentarily to allow adequate blood flow. Wait until your vision is corrected to resume physical activity or cease completely.
Low Blood Sugar
Hypoglycemia, or low blood sugar, could be the culprit of your impaired vision. Sugar in the bloodstream provides your body with energy, and engaging in long or demanding physical activities may use up a large amount of sugar in the body. In addition to blurry or impaired vision, low blood sugar is often accompanied by rapid heartbeat, dizziness, fatigue and hunger. To remedy the problem, eat something high in protein and nutrients immediately.
The most common cause of seeing stars is a result of head trauma. Even mild blows to the head can cause light flashes, colors and blurry vision to occur. If you recently engaged in a contact sport such as soccer, basketball, football or hockey, it may be the cause of your vision issues.
In some cases, flashing lights or blurry vision is a sign of a future migraine headache. This is especially true if you experience the vision problems in both eyes. The headache can range from mild to severe. If you suspect an oncoming headache, follow your physician's instructions for treating it. Light flashes may also occur without a headache and are referred to as an ophthalmic migraine, notes AllAboutVision.com.