Most people have natural vision changes after they reach age 40.
The main issue with vision over 40 is presbyopia, which means that you find yourself holding that restaurant menu at arm’s length to see it better. When you begin to see blurry text and have trouble with computer glare it is time to get a good pair of prescription reading glasses.
Presbyopia is normal but progressive. The lens of your eye becomes less flexible and cannot focus on close objects. This is why you are suddenly holding books at a distance. Other issues can be glare or color shade distinction. Presbyopia continues to decline through your 40s and 50s but slows down by age 60.
While it is tempting to buy reading glasses at the dollar store, you will use them daily and need a comfortably fitting frame with a prescription tailored to your eyesight. Also, after age 40 it is best to have a licensed optometrist examine your eyes every two years. They are trained to look for many different kinds of eye problems, not blurry vision. Diabetes, high blood pressure and medications for various other health issues are all linked to vision changes.
Some people who wear single vision glasses balk at the idea of switching to dowdy bifocals. Consider progressive lenses, which look better than bifocals and hide the need to use reading glasses. The lens is made with a seamless integration of distance, middle and near visions. Progressive lenses fit your natural gaze with no jump in vision as you look up and down.