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.

A woman wearing glasses holds one hand over her right eye during an eye test.

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 6.1 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 ran throughout 2016, screened schoolchildren in Cambodia, Ethiopia, Ghana and Senegal for health problems such as poor vision.

As part of the project, teachers were trained to carry out basic eye tests and refer children for further treatment. During the project, 57,400 children were screened for eye problems and 1,000 were given spectacles.

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

Find out about other eye conditions we treat

Protecting sight

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A collage of images featuring men, women and children wearing glasses.

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On 14 October 2021, Sightsavers staff, partner organisations and supporters celebrated World Sight Day to raise awareness about the importance of access to good eye care.

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A screengrab from Sumrana Yasmin and Mutave Mutemi video interview.

Blogs / Eye health /

In an interview for World Sight Day 2021, Sumrana Yasmin, Sightsavers’ global technical lead for eye health, talks to Mutave Mutemi about her work, the global eye health crisis and how we all have a part to play in addressing it.

Sightsavers, October 2021

Nine-year-old Khadijah at school with her friend after successful cataract surgery.

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

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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).