Refractive Error FAQs

Refractive error faqs


What is refractive error?

Refractive error is a common disorder which occurs when the eye cannot focus light rays (images) clearly on the retina, which results in blurry vision. The main types of refractive errors are myopia (near-sightedness), hyperopia (far-sightedness), astigmatism (irregular vision), and presbyopia (loss of near vision with age).

How are refractive errors caused?

Refractive errors are caused due to irregularities in the length of the eye, curvature of the cornea, and curvature of the lens, or age-related changes to the lens capsule. These irregularities and changes to the lens cause light rays to focus in front of the retina, behind the retina, or focus on more than one point on the retina, which results in a blurred image.

Myth or Fact – Some people may not know that they have a refractive error

Fact – While most people with a refractive error have symptoms of visual discomfort or blurred vision and visit an ophthalmologist to get their eyes examined, some people may fail to recognize that they are not seeing as clearly as they could. An annual eye exam can identify any existing problems with your vision and let you know if you are seeing as clearly as possible.

Common symptoms of refractive errors

The most common symptom of a refractive error is blurred vision. Patients report symptoms of eye strain and blurring, with difficulty in prolonged reading. Symptoms of double vision, haziness, glare or halos around bright lights, squinting and headaches may also occur.

Who is at risk for refractive errors?

Refractive errors are very common and are one of the leading causes of visual impairment in both children and adults. While presbyopia affects most adults over the age of 40, children who spend time on reading and on digital devices indoors are more likely to be affected with myopia than those who spent more time outdoors. Children with parents who have certain refractive errors may also be more likely to develop one or more refractive error in their lifetime.

Myth or Fact – Refractive errors can be prevented

Myth – According to The World Health Organization (WHO) refractive errors cannot be prevented. However, refractive errors can be diagnosed by an eye examination and treated with corrective glasses, contact lenses or refractive surgery. If detected early and corrected in time, refractive errors will not hinder the full development of good visual function.

How are refractive errors diagnosed?

A refractive error can be diagnosed with a test known as refraction during a comprehensive dilated eye examination, either with a computerized instrument (automated refraction) or with a mechanical instrument called a phoropter (manual refraction). The ophthalmologist uses an assortment of lenses to determine the type of corrective eye glasses or contact lenses that can help the patient’s eye focus better for clearer vision.

Can refractive errors be treated?

Refractive errors can be corrected with corrective lenses such as eye glasses or contact lenses (in adolescents and older people). These are prescribed during regular follow up visits to an ophthalmologist, who ensures a comprehensive evaluation. Laser eye surgery (LASIK) may also be used to correct some refractive disorders. Patients with corrected refractive errors have a better quality of vision, thus improving quality of life.

Myth or Fact -Refractive errors are not a serious concern

Myth – Undiagnosed and uncorrected refractive errors can lead to irreversible decrease in vision in one eye or both eyes depending on the severity, especially in children, who are also at risk to develop lazy eye.  The WHO estimates that 153 million people live with visual impairment globally due to uncorrected refractive errors. Vision impairment can lead to poor quality of life due to missed education and employment opportunities, lower productivity, etc.


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