As we age, the jelly-like structure called the vitreous which holds the shape of our eyes becomes more liquefied, and may tug/pull on the retina, which may cause tiny amounts of retinal pigment/tissues to come apart and float in the vitreous, which we call floaters. Remember, theses floaters cast a shadow on the retina, so you can see them. It’s normal to see a few floaters in either one or both eyes (we just ignore it), but if you’re seeing a lot of new floaters (either black or clear spots or a spider-like web) in your vision with constant flashes of light (like lightning bolts), then it may be a more serious sign that the vitreous is pulling on the retina and is causing a tear in the retina, which may cause fluid to leak through into the retina, and may lead to a detached retina, which may cause you to see a gray or black curtain of vision. If that occurs, then you will need to be referred immediately to a retinal specialist for surgery to repair the retinal detachment to prevent further vision loss.
If you are concerned about your floaters then I would recommend seeking care from an eye care professional for an ocular health assessment that includes a dilated eye exam. At the visit, your eye doctor may use dilating eye drops to view the back of your eye. These drops will enlarge the black colored structures in front of your eye that allow light to enter your eyes called the pupils, so that your eye doctor can shine light and utilize specialized lenses to get a better view of the back of your eye. There are possible side effects to the eye drops such as light sensitivity and difficulty reading up close for a couple of hours, so it’s best to bring your sunglasses to the visit. So to reiterate, if you are seeing a lot of new floaters and/or flashes of light, then go seek the care of your eye care professional immediately.