We see patients almost every month who have experienced sudden dramatic visual effects that can quite scary, especially the first time it happens.
The most common cause for this is an ocular migraine, which fortunately is quite benign and harmless. However, it is important for us to differentiate the patient’s symptoms from other forms of visual distortion or flashing lights that might be caused by something more serious or vision threatening.
We don’t understand completely why patients get migraines of any form but we do know they can be triggered by certain stressors and that they are associated with temporary erratic blood flow to parts of the brain or body. In the case of ocular migraine the blood flow disturbance is in vision processing portion of the brain known as the visual cortex.
Characteristics of Ocular Migraine:
The symptoms of ocular migraine can be very different for different people or even between different episodes for the same person but here are some of the most common complaints.
- The visual disturbances typically last from 5 to 30 minutes but can last much longer
- It can be in only one eye or in both
- A jagged circular line that shimmers, pulsates or moves is very common.
- Blank areas in the vision are common, either as a central spot or more peripherally, even causing “tunnel vision”.
- It may start small and grow larger before fading away
- There can be a waviness in the vision like “heat waves” or the “mirage effect”
- The visual symptoms may be followed by a mild headache (if followed by a significant migraine headache we would classify the episode as a “classic migraine” and not an ocular migraine)
- Some people experience ocular migraines frequently; others may have only one or two episodes in their lifetime.
Triggers are factors that may elicit a migraine headache or an ocular migraine. In many cases no trigger can be identified but possible causes include:
- Lack of sleep
- Bright lights or flickering lights
- Certain foods, drinks, or food additives
- Hormonal changes
- Changes in barometric pressure (incoming bad weather)
- Medications, including birth control pills
If you experience a sudden, dramatic visual effect or change you should contact your eye doctor or your physician to establish the cause. Fortunately, in most cases there isn’t a serious issue but it is possible that there is a vision threatening or significant health-related cause of the problem so you’ll want to speak with your doctor or, better yet let him/her evaluate the situation.
NOTE: the information provided is for informational purposes only and is not intended to serve as a substitute for evaluation by a medical professional. If you are experiencing significant visual problems you should seek examination by an eye care professional as soon as possible.