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Have you ever seen a temporary black spot in your vision? How about jagged white lines? Something that looks like heat waves shimmering in your peripheral vision?
If you have, you may have been experiencing what is known as an ocular migraine. Ocular migraines occur when blood vessels spasm in the visual center of the brain (the occipital lobe) or the retina.
These optical migraines can take on several different symptoms, but they typically last only from a few minutes to an hour. They can take on either positive or negative visual symptoms, meaning they can produce what looks like a black blocked-out area in your vision (negative symptom), or they can produce visual symptoms that you see but know aren’t really there, like heat waves or jagged white lines that look almost like lightning streaks (positive symptoms).
Some people do get a headache after the visual symptoms but most do not. They get the visual symptoms, which resolve on their own in under an hour, and then generally just feel slightly out of sorts after the episode but don’t get a significant headache. The majority of episodes last about 20 minutes but can go on for an hour. The hallmark of this problem is that once the visual phenomenon resolves the vision returns completely back to normal with no residual change or defect.
If you have this happen for the first time it can be scary and it is a good idea to have a
Eye doctors typically pride themselves on being able to improve someone’s vision through glasses or contact lens prescriptions. Whether it’s a first-time glasses wearer, or someone having either a small or large change in their prescription, we like to aim for that goal of 20/20 vision.
Despite our best efforts, however, correcting vision to 20/20 is not always a positive outcome for the patient. Whether someone will be able to tolerate their new prescription is based on something called neuroplasticity, which is what allows our brains to adapt to changes in our vision.
You or someone you know may have had this happen: Your vision was blurry, so you went to the eye doctor. The doctor gave you a new prescription, but after you received your new glasses, things seem “off.”
Common complaints are that the prescription feels too strong (or even too clear!) or that the wearer feels dizzy or faint. This is especially true with older patients who have had large changes in their prescriptions, since neuroplasticity decreases with age. It is also more likely to happen when the new prescription has a change in the strength or the angle of astigmatism correction. Conversely, this happens less often in children, since their brains have a high amount of plasticity.
Quite often, giving the brain enough time to adapt to the new vision will decrease these symptoms.
Whenever a patient has a large change in prescription, I tell them that they should wear the glasses full
