They are triggered by traction pulling on the retina. Normally when light enters your eye, the retina transmits information from these light signals through the optic nerve and on to the brain. We eventually interpret these signals as “light”. However, when that external force pulls at the retina, it is interpreted the same way, hence the sudden flash for bright light.
Since flashes could preempt something serious like retinal detachment (which causes blindness), it is imperative that any experience of flashes prompts a visit to your optometrist for assessment immediately.
The vitreous gel in our eyeball becomes, over time, more like a liquid. This transition also produces small flecks of natural protein which hover around in this liquid, occasionally passing behind the retina and casting shadows. These shadows are interpreted by the brain as dark blobs or patches moving across your field of vision.
Some individuals will be very used to their floaters by now: they’ve come, they’ve stayed and they aren’t going anywhere. However, if there is a noticeable change to the size, shape, number or activity of your floaters, then it’s time to make an appointment and assess your overall eye health as soon as possible.