Do you still have perfect vision 20/20 at your age?
First off, you need to know that 20/20 does not mean "perfect vision." It just means normal, typical distance visual acuity (sharpness). [Most young people can actually see better than that at distance, if only with contact lenses or glasses.]
By the time we reach middle-age and definitely in our 60s and 70s, we have experienced some degree of visual decline. This may not be detectable if you are relying only on the 20/20 line from a vision chart. For example, the slow, inexorable hardening and discoloration of the natural lens of the eye causes a decrease in contrast sensitivity and dynamic range of vision. This may be noticeable only at night but is still there during the day.
Other parts of the eye decline in function as well: macular problems and glaucoma typically do not appear until later stages of life. That is why it is a good idea to see an eye doctor once a year after age 40 or so.
_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic