Refractive Errors and the Working of the Human Eye

Refractive Errors and the Working of the Human Eye

Refractive Errors and the Working of the Human Eye

Refractive errors are common eye conditions and can be fixed. To understand refractive errors, we first need to understand how the human eye works. The light entering our eyes bends (refracts) to form a signal for the brain to create an image for us to see; that is how we’re able to see things around us.

However, vision issues like myopia, astigmatism, and presbyopia cause refractive errors, which can be corrected using contact lenses, glasses or refractive surgery. To understand what causes refractive errors, eye care specialists at Feel Good Contact (UK’s leading contact lens retailer and stockist of eye wear) are here to take you through the basics of the working of the human eye.

How the eyes see

Here are some easy steps to understand how the human eye works. Remember that the whole process starts with light.

  • Firstly, light passes through the cornea (the transparent curved outer layer of the eye) making its way to the pupil (the black circle in the centre of the iris).
  • The iris (the colourful part of your eye) will control the amount of light the pupil lets in.
  • Following the pupil, the light passes through the lens. At this stage, the cornea and lens work together to bend the light rays (refraction) to focus the light correctly onto the retina (present at the back of your eye, helps to send signals to the brain).
  • Here the photoreceptors (light sensitive cells – present in the retina) turn the focussed light into electrical signals.
  • These electrical signals travel from the retina to the brain through the optic nerve (a communication cable between the eyes and the brain).
  • The brain captures these signals and turns them into images you see.
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Voila! This is how you can see this article right now. But then you must be wondering how people get vision issues like blurry or distorted vision. The answer is refractive error.

Types of refractive errors

Refraction is the bending of light rays as they pass through one object to another. Regarding the eyes, light passes through the cornea; the lens and cornea then work as a team to bend the light rays and focus them onto the retina.

Refractive errors are vision problems that makes it hard to see things clearly. They happen when the light is not focussed correctly onto the retina. The primary refractive errors are:

  • Short-sightedness (myopia) – this is the most common refractive error. The cause is not entirely clear; however, increased screen time and extended near vision tasks are suspected causing this eye problem. In this condition the light is focussed on a point in front of the retina, instead of focussing on the retina, causing blurriness in distant objects.
  • Longsightedness (hyperopia) – this is caused when the eye fails to focus the light on the retina properly. In hyperopia, the light is focussed behind the retina, instead of focussing on the retina. This causes blurriness in seeing closer objects. In contrast, further-away objects may seem to be relatively clear.
  • Astigmatism – this vision problem occurs due to imperfection in the curvature of your eye’s cornea or lens; causing blurred and distorted vision at near and far distances.
  • Presbyopia – an age-related eye condition that diminishes the eye’s ability to focus on close-up objects. This condition usually occurs from about the age of 40 and is the most common form of near vision loss. This condition causes people’s vision to become blurry when they try to read or focus on small details.

Symptoms and causes of refractive errors

The following are symptoms of refractive errors:

  • Double vision
  • Hazy vision
  • Squinting
  • Headaches
  • Eyestrain
  • Seeing halos around bright light
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How to correct refractive errors

The first step towards correcting your refractive error is to get an eye test. Your optician/ eye care professional can determine the type and degree of refractive error your eyes possess. This is done through a test called refraction.

You may have more than one type of refractive error. Your optician will provide you with a prescription, and you can get the right eyeglasses or contact lenses for yourself. For instance, toric contact lenses can be prescribed for astigmatism.

There is a third option too – eye surgery, like laser eye surgery; this method can be beneficial in changing the shape of your cornea to fix the refractive error. Your eye care professional will be able to suggest the best form of correction according to your refractive error.


If you’re experiencing blurred vision or having issues seeing things clearly, consult your eye care professional.

Vision aids like contact lenses and glasses can correct refractive errors. You can learn more about vision aids at Feel Good Contacts and even purchase them online. Whether you’re experiencing vision issues or not, regular eye tests are recommended. Usually, eye test is recommended every 2 years unless your optician advises you to go sooner or if you are having any problems then it’s crucial to contact your eye care professional immediately.  It is better to be cautious about your eyesight than wait for it to get worse!