What are refractive errors and how are they corrected?
If you have trouble seeing nearby or distant objects, you may have a refractive error. This means the lenses in your eyes aren’t focussing light correctly. It leads to other problems as you struggle to see during everyday tasks. Refractive errors affect a huge number of people. This page will help you understand the condition and the different ways to treat it.
What are refractive errors?
Let’s start by explaining what refraction is. During refraction, light rays bend as they pass through an object. The transparent front part of the eye, called the cornea, and the lens inside the eye both refract light. This enables light to focus on the retina – the layer at the back of the eye that converts images into signals for the optic nerve.
If the shape of the eye changes, it also alters how light rays bend and focus. When the eye cannot focus light on the retina to create a shar image then it results in a refractive error. The term covers several conditions, which we explain below.
Refractive errors can range from mild to severe. Go to Refractive error symptoms on this page for more about these.
Types of refractive error
There are four common types of refractive error:
- Myopia, also known as short-sightedness or near-sightedness (objects that are far away look blurred)
- Hyperopia, also known as long-sightedness or far-sightedness (close objects look blurred)
- Astigmatism, where your vision looks blurred (usually at all distances) due to an elongated eyeball shape
- Presbyopia, or problems focussing on close objects as you get older (normally around middle age).
Find out more about eye conditions from Consultant Ophthalmologist, Mr Tariq Ayoub, in the playlist below.
Refractive error symptoms
Many eye conditions produce symptoms right away, but problems with refractive errors can be subtle at first. Many people don’t notice these symptoms until they are more pronounced.
Symptoms of refractive errors include:
- Blurred or hazy vision
- A glare or halo around bright lights
- Eye strain (tired, sore eyes)
- Problems focussing when reading or using a computer
Refractive error conditions are common, so it’s important to get eye examinations every two years. If you already wear glasses or contact lenses and experience any of these symptoms, you might need a new prescription.
Refractive error causes
Refractive errors are an unfortunate but completely natural characteristic. As time passes, our eyes can naturally vary in shape or density, especially during childhood or when we reach our 40s.
Anyone can develop refractive errors, but they frequently run in families. For example, myopia is often an inherited condition. And it’s generally discovered before a person reaches adulthood.
Refractive errors may happen when the length of the eyeball grows too short or too long. For some people a problem with the shape of the cornea (the eye’s transparent outer layer) causes refractive errors.
The crystalline lens inside the eye is particularly affected by ageing. It can lose its clarity in later life, making your sight deteriorate. If you have refractive errors before middle age, you can also develop presbyopia on top of your other condition when you get older.
Read on for help in taking the next steps to improving your vision.
Refractive error correction
Correcting refractive errors is often easy to do with glasses or contact lenses. An alternative to wearing glasses or contact lenses is having vision correction surgery.
Ophthalmologists (eye doctors) check for refractive errors during a standard eye test. They do this by asking you to read letters from a chart and checking the effect of different lenses.
If you need corrective lenses, you’ll get a prescription for the right kind of glasses or contact lenses.
Some types of surgery, like laser eye surgery, change the shape of your cornea to fix refractive errors. At Oculase we can help you decide if surgery is the best option.
Laser eye surgery is a simple corrective procedure to treat all kinds of refractive errors.
For some patients, laser eye surgery might be unsuitable for presbyopia (age-related focussing problems). In these cases we may offer refractive lens exchange (lens replacement surgery). For this procedure, an Advanced Technology Lens replaces the natural lens. Its benefits include a much-reduced need to wear glasses or contacts, and no risk of developing cataracts.
An Implantable Contact Lens is an alternative to laser treatment, especially if you need a high eyesight prescription. We implant a custom-made refractive lens on top of your natural lens, enabling you to see better without glasses or contacts.
A Refractive Secondary Lens Implant is for people who’ve had cataract or lens replacement surgery and still need glasses. After this surgery (which involves placing a second lens implant on top of the existing lens implant), you’ll be able to perform most activities without spectacles.
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Vision correction is available for refractive errors and other eye conditions. It’s important to be aware of treatment options so you can make an informed decision about your eye care.
For any questions about clinical eye treatments, contact us to talk to a specialist.