If you purchase prescription glasses to resolve vision problems, it’s important to know that they aren’t a permanent solution. Your eyes will continue to change, and eventually, you’ll need to update your prescription. Below is a guide on prescriptions to help you keep enjoying improved eyesight for years to come.

How Prescriptions Work

A prescription contains numbers related to aspects of your vision that need to be corrected. O.D. (ocular dexter) refers to your right eye and O.S. (oculus sinister) is your left eye.

SPH (sphere) is the prescription power, which helps nearsightedness (-) or farsightedness (+). CYL (cylinder) indicates astigmatism, a condition in which an irregular cornea shape causes blurry vision. AXIS explains the degree of astigmatism.

How Long They Typically Last

The average prescription for glasses is valid for two years. This drops to one year for contact lenses.

If you’re approaching this mark, it’s important to schedule a checkup with your eye doctor. A store may not accept an expired prescription. 

Why They Change

Your eyes will inevitably change as you age, which is why your prescription will need to be updated. Most people’s visions complete development by age 19. The eyes themselves may change until age 21.

At age 40 and above, you may become more susceptible to age-related decline and diseases like glaucoma, cataracts, and macular degeneration. These all impact your vision and require updated prescriptions. Other factors, including eye strain and dryness caused by computer use, also contribute to fluctuating eyesight. 

If you’re interested in getting glasses or need to update your prescription, stop by Cohen’s Fashion Optical in New York City. Based in the Upper West Side and serving all of Manhattan, this practice has helped patients since 1927. They carry a large selection of glasses, sunglasses, and contact lenses. Learn more about eye health on their website or call (212) 769-1410 to schedule an appointment.