Skip to main content
Home » Our Blog » Dr. Small answers a question about spot flashes on the “Ask a Doctor of Optometry” Facebook group

Dr. Small answers a question about spot flashes on the “Ask a Doctor of Optometry” Facebook group

Question: I see spot flashes in the outside corners of my eyes. Not all the time, but if it starts in the morning then i see the flash throughout that day, none today.

optometrist Winnipeg, MBAnswerThanks for the great question Doris. I see patients on a daily basis that describe similar symptoms. My goal is to try and differentiate between flashes in peoples vision that are due to what we call an ocular or ophthalmic migraine and those that are secondary to traction from the vitreous gel inside the eye. Ocular migraines are accompanied by something called scintillating scotomas. Everyone describes these differently but scotomas occur when parts of the visual field are blocked. Often in these cases they are blocked by a kaleidoscope like flashing light that emanates from both eyes. Patients often describe being able to see these effects even with their eyes closed. These usually last anywhere from 5 to 60 minutes and can sometimes be followed by headaches. Dehydration, stress, lack of sleep, caffeine and certain foods are typical triggers for ocular migraines.

When someone describes their flash stemming from only one eye and it is a quick flash usually only seen in the dark almost like a flash from a camera then I often attribute this to the vitreous gel. This gel fills the largest cavity within the eye and presses right up against the inner lining known as the retina. As everyone has more birthdays (my best way to describe getting older) this gel changes somewhat and tends to move around more causing it to actually separate itself from the retina. As it does this it can also have certain areas where it pulls and tugs on the retina as you move your eye around and it sends a message to your brain that you are seeing light (flash) when there isn't any actual light there.
Typically patients see this less during the day because the flash tends to blend in with the lit background. Often they are also associated with new vitreal floaters (a change in the vitreous composition that causes portions of it to be less translucent and we end up seeing spots or as my patients often describe "bugs" floating around in their vision). As you can imagine sometimes if the vitreous is adhered strongly to the retina and begins to separate it can also cause in rarer cases what we call a retinal tear. Retinal tears can then lead to retinal detachments and this can cause a permanent loss in vision.
No matter which of these two descriptions match your symptoms most closely, you should be seen by a doctor of optometry in Winnipeg as soon as possible. The reason for this is to rule out that you don't have a retinal tear or detachment that may be causing your symptoms. Not always, but more often a retinal tear will cause your flashing to increase (and not last minutes at a time like with an ocular migraine) and will be accompanied by an increase in floaters as well. A change in your peripheral vision may also occur and if the retinal tear turns into a retinal detachment then patients often describe a veil or gauze like change to their peripheral vision. It is possible that if the flashing is due to vitreal traction that these flashes spontaneously stop once the vitreous has separated from the retina cleanly and hasn't caused any damage. No matter what the case may be your eyes need to be looked at to rule out all of these possibilities. Expect to be dilated (drops used to make the pupils larger) so that your Winnipeg eye doctor can see the retina and vitreous through a larger window. If he or she finds a retinal hole, tear or break then he or she will refer you to a retinal specialist for assessment and potential surgical treatment.

Visit the "Ask a Doctor of Optometry" Facebook group.