Myopia, also known as shortsightedness or nearsightedness, is a common eye condition that affects distance vision. A person with myopia can usually see close objects clearly, but distant objects appear blurred.

Myopia is becoming more common across the world, especially in children. Researchers and eye care professionals link this increase to lifestyle changes, including higher screen use and reduced time spent outdoors.

This guide explains what myopia is, what causes it, how it affects vision and which treatment options are available.

Myopia is a refractive error that affects how light focuses inside the eye. A refractive error is a vision condition caused by the shape of the eye changing how light reaches the retina.

In a healthy eye, light focuses directly on the retina. The retina is the light-sensitive layer at the back of the eye.

In a myopic eye, the eyeball is usually too long from front to back, or the cornea is too curved. The cornea is the clear front surface of the eye. These changes cause light to focus in front of the retina instead of directly on it. As a result, distant objects appear blurred.

People with myopia often see nearby objects clearly. Reading, using a phone or working on a computer may feel comfortable. Activities that rely on distance vision, such as driving or watching television, are usually more difficult.

Myopia is the opposite of hypermetropia, also called long-sightedness. Hypermetropia causes nearby objects to appear blurred while distant objects remain clearer.

Myopia affects around one third of people in the United Kingdom. Rates of myopia in children have increased significantly over the last 50 years.

Researchers observed a further increase in myopia cases during the COVID-19 pandemic due to increased screen time and reduced outdoor activity.

Opticians measure glasses and contact lens prescriptions in diopters, written as "D". A diopter measures the focusing power needed to correct vision.

Myopia prescriptions use negative numbers. A higher negative number usually means stronger myopia.

• Low myopia: -0.50 D up to -3.00 D.
• Moderate myopia: Between -3.00 D and -6.00 D.
• High myopia: -6.00 D or worse, which can lead to serious eye complications such as glaucoma.

People with myopia often experience symptoms related to blurred distance vision.

Common symptoms include:

• Blurred vision when looking at distant objects
• Squinting to improve focus
• Eye strain or aching around the eyes
• Headaches caused by visual strain
• Difficulty seeing road signs, classroom boards or television screens

Children may not realise their vision is blurred because the change can happen gradually. Regular eye tests help detect myopia early.

High myopia can increase the risk of additional eye conditions - such as cataract, glaucoma or retinal detachment - because elongation of the eyeball.

• Retinal tears and retinal detachment: The retina can stretch and thin as the eyeball becomes longer. This stretching increases the risk of retinal tears and retinal detachment. Retinal detachment is a serious medical condition that requires urgent treatment.
• Glaucoma: People with high myopia have an increased risk of glaucoma. Glaucoma damages the optic nerve, often due to increased pressure inside the eye. The optic nerve carries visual information from the eye to the brain.
• Cataracts: Myopia may increase the likelihood of developing cataracts earlier in life. A cataract causes the lens inside the eye to become cloudy, which reduces vision clarity.
  

Myopia in children has increased globally over recent decades. Researchers associate this increase with major lifestyle changes. Children now spend more time indoors and more time using digital devices.

The COVID-19 pandemic accelerated these changes. During lockdown periods, many children spent less time outdoors and more time on screens for education and entertainment.

Research suggests environmental factors play a major role in rising myopia rates because genetic changes cannot occur rapidly across a single generation.

Environmental factors and genetics work together. Genetics may increase susceptibility to myopia, while environmental exposure influences how quickly myopia develops and progresses.

Myopia cannot currently be cured. However, treatment and lifestyle adjustments may help slow progression, especially in children. Eye care professionals refer to this approach as myopia management.

Research shows that specially designed glasses lenses and contact lenses may reduce myopia progression in children by approximately 50% to 60%.

Myopia often progresses during childhood and teenage years because the eyes are still developing.

For many people, myopia stabilises during early adulthood. However, progression can continue in some cases.

Children diagnosed with myopia at a younger age are more likely to develop high myopia later in life if the condition is not managed.

Regular eye tests support early diagnosis and monitoring. Early intervention may reduce the risk of severe progression. 

An optician can usually diagnose myopia during a comprehensive eye examination.

During the appointment, the optician will ask about symptoms, medical history and changes in vision.

The eye examination may include:

• Vision tests using letter charts
• Prescription measurements
• Eye health assessments
• Retinal examinations
  

The optician will explain the results and discuss suitable treatment options.

If you think you or your child may have myopia, booking an eye test is an important next step.

Early diagnosis supports effective management and helps monitor changes in vision over time. An optician can recommend glasses, contact lenses or myopia management solutions based on individual needs.