Why can your prescription change over the years, even in adulthood?

Have you noticed that your glasses no longer correct your vision as well as they used to? Although it is often thought that eye prescription stabilises in adulthood, visual changes are more common than you might imagine. In this article, we explain why your prescription can vary over the years, even in healthy adults, and when it is advisable to have an eye check.

What do we mean by visual prescription?

Prescription refers to the number of dioptres a lens needs to correct visual defects such as myopia, hyperopia (long-sightedness), astigmatism, or presbyopia. This measurement is obtained through an optometric examination and is expressed in positive or negative values, depending on the type of condition.

Why can prescription change in adults?

Although it is normal for dioptres to increase during childhood and adolescence, changes can also occur in adulthood. During the early decades of life, prescription tends to evolve naturally due to genetic and environmental factors, such as eye development, visual habits, or the amount of time spent on near work. In most people, this progression tends to stabilise upon reaching adulthood, although it does not always remain completely fixed over the years. Below, we explain the main causes:

Age-related physiological changes

• From the age of 40–45, presbyopia (age-related long-sightedness) appears, a progressive loss of the ability to focus at close distances.
• At more advanced ages, the crystalline lens loses transparency and elasticity, also affecting prescription.

Changes in eye health

• The development of cataracts can induce a change in refraction, often towards temporary myopia (known as “second sight”).
• Conditions such as keratoconus, corneal alterations, or retinal diseases can also modify prescription.

Metabolic or systemic changes

• Diabetes: may cause temporary variations in vision due to fluctuations in glucose levels.
• Certain medications can also affect accommodation or corneal curvature.

Visual fatigue and the digital environment

• Excessive screen use promotes symptoms such as blurred vision or difficulty focusing.
• These do not always imply a real change in dioptres, but they do require attention and possible optical adjustments.

What signs indicate that your prescription has changed?

Some warning signs include:

• Difficulty reading or seeing at a distance.
• Frequent headaches at the end of the day.
• Eye strain when using screens.
• The need to move objects closer or further away to focus.
• Double or blurred vision.

How can you maintain good visual health in adulthood?

Some key recommendations:

• Have regular eye check-ups, even without symptoms.
• Maintain good lighting at home and at work.
• Follow the 20-20-20 rule: every 20 minutes, look for 20 seconds at something 20 feet (6 metres) away.
• Do not use glasses purchased without a proper prescription.

Changes in prescription are not exclusive to children or adolescents. In adults, they can also occur due to multiple causes, from ocular ageing to systemic factors. At Barraquer, we are committed to providing you with a thorough diagnosis and personalised treatment so that you can always enjoy the best possible vision.

Dr. José Lamarca, ophthalmologist at the Barraquer Ophthalmology Centre