What is refractive error?

Refractive errors are eye disorders caused by irregularity in the shape of the eye. This makes it difficult for the eyes to focus images clearly, and vision can become blurred and impaired.

Refractive errors include eye problems such as myopia (short-sightedness), hyperopia (long-sightedness) and astigmatism (caused by an irregularly curved cornea).

They also include presbyopia, a normal ageing change, where the eye is no longer able to focus at close range.

These eye disorders can be particularly problematic in developing countries, where those affected may not be able to afford sight tests or spectacles to help improve their vision. What’s more, those living in rural areas may not have access to eye care – in sub-Saharan Africa, for example, two-thirds of ophthalmologists and optometrists are based in capital cities, leaving a shortage of trained eye care professionals working in rural areas.

161 million

people have refractive errors worldwide

3.5 million

people are blind due to refractive errors

2 billion

people are short-sighted worldwide

How is refractive error treated?

Eye test

The patient is given an eye test to find out how their vision is affected.

Diagnosis

During the test, they're asked to read letters or symbols on a chart.

Monimala, an elderly woman from India, smiles while wearing her glasses.

Correction

If they have refractive error, it can then be corrected with spectacles.

What we’re doing

Since 2004, Sightsavers has dispensed seven million pairs of spectacles across Africa, Asia and the Caribbean as part of our work in universal health care.

We have also helped to train 735 optometrists and 437 optometric technicians, who are able to carry out sight tests, diagnose eye problems and help to treat people with low vision in some of the poorest parts of the world, who may otherwise not have access to eye healthcare.

Sightsavers’ School Health Integrated Programming (SHIP) project, which started in 2016, has screened schoolchildren in Cambodia, Ethiopia, Ghana, Senegal, Liberia and Pakistan for health problems such as poor vision.

As part of the project, teachers have been trained to carry out basic eye tests and refer children for further treatment. More than 150,000 children have been screened for eye problems, and thousands of students have been given spectacles.

Download Sightsavers refractive error strategy (pdf) to read more about our work to treat refractive error.

Find out more about Sightsavers’ eye health work

How we protect sight

More about refractive error

Twelve-year-old Arthur smiles as he stands next to his teacher, Mr Thompson. They stand in front of a chalk board in a classroom.

Blogs / Eye health /

In line with World Sight Day’s focus on child eye health, our experts reveal why eye screenings in schools are boosting students’ academic performance.

Sightsavers, September 2024

Patience from Liberia wearing her new glasses, whilst standing next to her mother, betty.

Blogs / Eye health /

Glasses can be life-changing for someone with refractive error. That’s why we’ve joined the World Health Organization’s SPECS 2030 initiative.

Sumrana Yasmin, May 2024

Arthur in the classroom, smiling while wearing his new glasses.

News / Eye health /

SPECS 2030 aims to tackle the world’s biggest cause of visual impairment by improving global access to eye care.

May 2024

Nine-year-old Khadijah at school with her friend after successful cataract surgery. They're sitting at a desk writing on a shared piece of paper, wearing their blue school uniforms.

Nine-year-old Khadijah (right) is no longer at risk of going blind.

Will you help us ensure more children can enjoy a future free from blindness?

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What is refractive error?

Refractive errors are eye disorders caused by irregularity in the shape of the eye. This makes it difficult for the eyes to focus images clearly, and vision can become blurred and impaired.

Refractive errors include eye problems such as myopia (short-sightedness), hyperopia (long-sightedness) and astigmatism (caused by an irregularly curved cornea).