My Prescription Keeps Changing — Is That Normal?

Finding that your prescription is higher at every check-up can be worrying. For some people this is a natural, age-related pattern; for others, it signals progression that needs closer monitoring.

This page covers the most common causes of a rising prescription, when it needs closer assessment, and how an eye surgeon works through the concern.

A prescription that keeps rising over time usually means myopia (short-sightedness) is progressing. This is common during childhood and the teenage years, alongside the eye continuing to grow, and most change at that age is expected. If it keeps rising into adulthood, or rises faster than expected, the cause needs a closer look.

How quickly the prescription rises, the age it started, and whether it affects one or both eyes help a surgeon judge whether this is expected or progression needing follow-up — which is why previous prescriptions are a useful reference at the appointment.

The pace of change matters as much as the change itself: a small, steady rise each year points to an expected pattern, while large jumps over short periods, or a rise that speeds up in only one eye, may prompt a more detailed assessment.

The most common cause is myopia progressing naturally, tied to the eyeball continuing to grow at a young age; a family history of high myopia can make this more pronounced.

Less often, irregular contact lens wear and long periods focusing up close — screens, reading — are also linked with prescription change; screen time's role is still debated in the literature and not accepted as a cause on its own.

A rarer but important cause is a progressive corneal condition such as keratoconus, where the cornea thins and becomes irregular, usually with a noticeable change in astigmatism too. Temporary states such as dry eye or fluctuating blood sugar can also make the prescription swing, so not every change means permanent progression.

The mechanism behind natural progression is the eyeball's axial length continuing to grow; as the eye lengthens, the focus point moves further from the retina, and the prescription rises to match. This growth usually slows with age but can continue into adulthood in some patients. The diagram below summarises these causes by how common they are.

A persistently rising prescription usually points to progressing or high myopia; less often, it involves a marked change in astigmatism or an underlying condition such as keratoconus. Which applies to you can only be clarified with a detailed eye examination; below is a brief overview of each possibility.

Each condition follows its own course and needs a different assessment; for example, follow-up for high myopia focuses mainly on the prescription and the back of the eye, while suspected keratoconus calls for corneal topography and pachymetry. The exact cause can only be confirmed by examination — the information here is a general framework.

If the rising prescription comes with a sudden drop in night vision, floaters, flashes of light, or a shadow across your vision, this calls for a more urgent assessment. In eyes near or past the high myopia threshold, the longer eyeball means these symptoms may need a further look from a retinal perspective — covered on our retinal diseases page.

Without these symptoms, a rising prescription is not usually an emergency, and a routine eye examination is enough. Whenever you are unsure, the safest approach is to book an examination rather than judge the urgency yourself.

The surgeon first compares the change against your past records, so bringing previous prescriptions or old results to the appointment speeds up the assessment. A refraction test, corneal topography and, if needed, a fundus examination then look for the cause; reading these together clarifies whether the change is expected or progression needing closer follow-up. Our separate page covers how this fits into a full eye examination.

The order of these steps can be adapted to what you describe and what the examination shows; for example, an irregular topography finding may prompt further measurements to check for keratoconus. The diagram below summarises the general order this assessment follows.

Treatment depends on the cause, so this must be clarified first. If the prescription is not yet stable, or the rise is mild, updating the glasses or lens prescription with regular follow-up is usually enough; if it has reached the high myopia threshold and a permanent solution is wanted, surgery comes into the picture.

If corneal topography suggests keratoconus, the approach changes completely; the priority becomes stabilising the cornea, and permanent treatments wait until this is clarified. The same complaint can need different treatment in different patients, so the decision rests on an individual examination.

To find out what's behind your rising prescription and go through your options, you can book an appointment at Op. Dr. Anıl Kaya's clinic in Istanbul.

The examination checks whether your prescription is stable, your corneal structure, and the back of your eye; the result clarifies whether glasses or lens management, or a permanent option such as ICL or laser, is right for you.