HOW AGE AFFECTS VISION AND GLASSES PRESCRIPTION
The vision system and visual development is a very delicate system. Although as humans we are each different in our way and the rules vary dramatically, the following outlines common trends regarding the developing eye.
The refractive error (eye's prescription) at birth has a very large distribution showing that many things are happening by chance.
Vision Age 3
Things begin to change dramatically and the standard deviation of refractive error becomes smaller.
Emmetropization happens. This is a regulatory growth mechanism which is very obvious during the first few years of life that makes most people emmetropic (no refractive error) or very close to it.
The School Years Vision
In the 3rd to 5th grade a common form of nearsightedness called school myopia develops. This is most likely caused by a growth of the eye's axial length and develops faster in girls than boys.
If myopia occurs it typically develops at a rate of .43 diopters per year for girls and a rate of .40 diopters per year for boys.
New studies suggest that children that spend more time outdoors progress at a much slower rate of myopia.
Eyesight In The 20-40 Year Olds
In our twenties our eyesight begins to stabilize. Although it never stops changing, myopia progression reduces significantly. This is the age when LASIK becomes an option.
Eyesight In Middle Age (40-60)
The average refractive error in this population increases a bit. Although we are not certain why, one believe is the emergence of latent hyperopia, or farsightedness.
When one is farsighted or hyperopic, they are typically hyperopic from childhood. However, our eye has the ability to compensate with this error by using our eyes focusing system called accommodation. In our mid-thirties and early-forties we begin to loose our ability to accommodate, therefore accepting glasses prescription we may not have before.
This is much more common, and happening much earlier today with the high demand on our visual system with increased use of computers, tablets, and phones.
Vision After 60
As cataracts develop in the aging eye, it may cause a myopic shift in ones prescription. This shift for the farsighted person may lead to what is known as "Second Sight".
Second sight happens when the once farsighted glasses wearer has a nearsighted shift in their vision because of cataract growth. The shift brought the once farsighted person to emmetropia, or no glasses prescription.