Understanding Common Types of Refractive Errors
Refractive errors such as astigmatism, hyperopia, presbyopia, and myopia are common vision conditions. It is estimated that approximately one fifth of Australians over 40 have refractive errors.
Even though refractive errors are common, they can be confusing to tell apart. This guide to the different types of refractive errors will explain the difference between myopia, hyperopia, presbyopia, and astigmatism.
What Is a Refractive Error?
Refractive errors are a common vision disorder that relates to how the eyes focus light. In normal vision, images are focused on the back of the eye (retina). WIth refractive errors, the image does not focus where it should on the retina, leading to blurry vision.
Refractive errors can occur due to a misshapen cornea or lens, length of the eye, age, and lens flexibility.
4 Common Types of Refractive Errors
Myopia
Myopia, commonly known as near-sightedness or short-sightedness, causes far off objects to appear blurry. Myopia typically develops in young children, usually around 10 years old.
Cause: Usually inherited, caused by an eye that grows too long from front to back or if the lens or cornea is too curved
Symptoms: Difficulty viewing distant objects, eye strain, headaches
Treatment: Myopia treatment involves prescription eyeglasses or contact lenses featuring a minus or negative lens. Myopia requires close monitoring during adolescent years to ensure it is not progressing.
Hyperopia
Hyperopia, known as far-sightedness or long-sightedness, is the opposite of myopia. Farsightedness makes it difficult to see close-up objects.
For instance, you may be able to read a sign across the road but struggle to read the words on a screen in front of you. Most people with farsightedness are born with it.
Causes: Weak refractive power; short axial length; unusually positioned lens
Symptoms: Objects up close appear blurry in mild cases; in more advanced cases, vision is blurred at all distances
Treatment: Prescription glasses or contacts with plus or positive lenses to adjust the retina’s focusing power
Learn more about Myopia vs. Hyperopia in our guide here: Definition of Short Sighted and Long Sighted Key Differences.
Astigmatism
Astigmatism is a refractive error caused by an irregularly shaped cornea or lens. Typically, eyes are round. In cases of astigmatism, the eye is shaped like the back of a spoon or a football. This irregular shape distorts light as it enters the eye and bends it more than it should, resulting in blurry vision.
Causes: Irregular shaped lens and cornea that prevents light from being focused properly on the retina
Symptoms: Eye discomfort, eye strain, headaches, blurred vision, poor night vision, double vision
Treatment: Usually corrected with glasses or contact lenses that feature have an astigmatic power distribution
Learn more: Astigmatism Testing
Presbyopia
Presbyopia refers to the need for reading glasses. This common refractive error typically shows up with age. Presbyopia often begins around age 40 or older.
This refractive error is considered normal with age and can occur in individuals who previously had perfect vision. It is also known as age-related farsightedness.
Causes: Occurs when the eye lens hardens and the ability to focus decreases. This makes close-range reading more difficult.
Symptoms: Difficulty reading newspapers, computer screens, books, and other close-range reading activities
Treatment: Easily corrected with prescription reading glasses if no other refractive errors are present. If you already wear contact lenses or glasses, you may be switched to a multifocal lens.
| Refractive Error | Cause | Symptoms | Treatment |
|---|---|---|---|
| Myopia | Usually inherited; due to an eye that grows too long or irregular cornea curvature | Distant objects appear blurry | Prescription glasses or contacts with negative or minus lenses |
| Hyperopia | Results from the eye growing too short from front to back or from an irregular shaped cornea | Objects up close appear blurry | Prescription glasses or contacts with plus or positive lenses |
| Astigmatism | Irregular curvature of the cornea, irregularly shaped lens | Eye discomfort, eye strain, headaches, blurred vision, poor night vision, double vision | Glasses or contact lenses with astigmatic power distribution |
| Presbyopia | Lens hardening/decreased flexibility that naturally occurs with age | Difficulty reading up close | Corrective reading glasses or a multifocal lens |
Symptoms of Refractive Errors
Symptoms of refractive errors depend on the type of refractive error but may include:
Eye strain
General eye discomfort
Blurred near vision
Blurred distance vision
Blurred overall vision
Headaches
Eye fatigue
Double vision (diplopia)
Squinting
Difficulty concentrating
To learn more about the different types of refractive errors, including their symptoms, we recommend this excellent resource: Refractive Errors | HealthDirect.
How Are Refractive Errors Diagnosed?
Refractive errors can be diagnosed during an eye examination with an optometrist. Regular eye examinations are crucial for maintaining optimal vision.
At For Eyes Optometrist, our eye testing can detect all types of refractive errors through visual acuity tests, refraction, and accurate measurement of the corneal shape. These tests show how light is focused onto the retina and allow us to measure and correct refractive errors.
How Often Should Eye Examinations be Scheduled?
A child can be examined at any age. If any concerns arise, then we recommend an eye examination as soon as possible. If there are no concerns, then we still recommend that a child is examined around four years of age to ensure that they are “school ready” and that there are no concerns with their vision. Once your child has had an eye examination at For Eyes Optometrist, we will recommend a schedule for follow up eye examinations. That is, whether they would occur on an annual basis or alternative time frame.
For adults, we recommend that eye examinations are undertaken every two years. Beyond the age of 65 years, we recommend annual eye examinations to ensure that any eye conditions are appropriately diagnosed and managed.
You may need to attend more frequent eye exams if you:
Wear spectacle lenses or contact lenses, particularly with high or complex prescriptions
Have diabetes, or a history of diabetes in the family
Have a history of ocular pathology
Treatments for Refractive Errors
There are several treatments for refractive errors that help correct vision. Treatment typically begins with prescription lenses but your eye doctor will determine the most suitable treatment for your refractive error.
Treatment options for refractive errors may include:
Prescription glasses
Prescription contact lenses
Laser surgery to change the shape of the cornea
Lens-based surgery using an intraocular lens implant
Managing Refractive Errors
Refractive errors are common in Australia and worldwide. Fortunately, refractive errors can be easily diagnosed at a regular eye exam and treated with corrective lenses
Book an appointment with a member of our caring team today. For Eyes Optometrist specialises in myopia management, refractive error treatment, and children’s vision. Our team of optometrists, an orthoptist, and optical dispensers are here to tailor your treatment to help you see the world clearly.
Frequently Asked Questions
Can a refractive error be cured naturally?
No, it is not possible to cure refractive errors naturally. There are no natural ways to change the shape of the eye. Corrective lenses or surgery are options for managing refractive errors.
Can a refractive error be cured permanently?
Refractive surgery is the closest option for permanently correcting refractive errors. Procedures like LASIK change the cornea’s shape to correct how it focuses light. Not everyone is a good candidate for refractive surgery, so it is important to discuss treatment options with your optometrist or eye doctor.
How serious is a refraction error?
Refractive errors are a common vision problem and are generally not considered serious. Although refractive errors can affect daily life, they should not affect your overall health.
However, it is important to work with your optometrist to manage refractive errors. Left untreated, refraction errors may lead to eye conditions and complications. Early diagnosis and management is crucial in children to monitor refractive errors and ensure poor vision does not affect academic performance.
