Most visual difficulties can be attributed to nearsightedness, farsightedness, astigmatism, or a combination of the three.
It can be confusing to remember the differences between nearsightedness and farsightedness. In short, nearsightedness means the ability to see things nearby with relative clarity, while farsightedness is the ability to only clearly see objects that are far away.
Learn the differences between nearsightedness and farsightedness in more detail as well as their causes, diagnosis, and treatment.
In order to tell if you are nearsighted or farsighted, try to test which objects in your view are blurriest.
First, make sure your eyes are rested by looking away from any screens or closing your eyes for a few minutes.
Then, start by trying to read a few pages in a book. Do the words look blurry? Do you have a headache afterward? You may be farsighted.
Now, try looking at something in the distance from about 10 feet, such as a sign on the street or a poster on a wall. Are you unable to see words and shapes clearly enough to read or distinguish what they are? You may be nearsighted.
If you have difficulty seeing objects that are both near and far, it’s possible that you’re both nearsighted and farsighted. This can happen when each of your eyes develops its own condition. In fact, it’s possible to be nearsighted or farsighted to varying degrees in each eye.
If you believe that you’re nearsighted or farsighted, make an appointment with an optometrist for an eye exam to confirm a diagnosis and get treatment.
Nearsightedness is the ability to clearly see objects that are close to you but have difficulty seeing objects that are far away. It’s also known as myopia.
Causes
Our eyes help us see by converting light into images. When light hits our eyes, it travels from the cornea through the pupil and all the way back to the retina.
The retina is responsible for passing the light off to the optic nerve, which sends electrical impulses to the brain. When you are nearsighted, there is a refractive error, which means that light can’t be properly focused on the retina.
Refractive errors have to do with the shape of your eye. You can be born with a cornea that is too rounded or an eyeball that is too long, or you could develop these new shapes as you age and grow.
According to the American Refractive Surgery Council, myopia can be attributed to environmental issues like the use of computers, mobile phones, and electronic readers.
Symptoms
The main symptom of nearsightedness is noticing blurriness when trying to see objects in the distance. For example, having difficulty reading signs while driving, or troubles seeing handwriting on a whiteboard at school.
Because of the strain associated with forcing your eyes to focus throughout the day, you might notice these additional symptoms:
- headaches
- squinting
- eye fatigue or soreness
Risk factors and severity
Most diagnoses of myopia are in younger children since their eyes change shape as they grow. It is typical for adults to remain nearsighted if they were diagnosed as a child.
According to the American Optometric Association, adults can also become nearsighted due to visual stress or health conditions like diabetes.
A diagnosis of myopia can cover a large range. If you’ve ever taken an eye exam, think of the “E” chart with the letters that you have to read back to your optometrist or opthalmologist. Mild myopia can mean having difficulty seeing smaller letters on the eye chart, while high myopia can mean not being able to see the big “E” on the chart.
People may also experience “pseudo-” myopia. This is the result of overuse of the eyes’ focusing mechanism.
Farsightedness, also called hyperopia, means that you can clearly see objects far away but have difficulty seeing closer objects clearly.
Causes
Farsightedness is also based on the shape of the eye. The cornea and lens are the parts of the eye that refract incoming light into the retina. Once the retina receives the light, it passes it off to the optic nerve which carries the information to the brain.
Farsightedness is typically seen in cases where the cornea is flat, or the eyeball is shorter than normal. This condition is most likely inherited through your genes.
Symptoms
People who are farsighted may have difficulty reading, and may experience the following:
- squinting
- pain, burning, or aching around the eyes
- headaches associated specifically with reading, or other tasks that require focus on nearby objects
Risk factors and severity
Children with farsightedness may develop strabismus (crossed eyes) when the condition hasn’t been diagnosed and corrected.
According to the College of Optometrists in Visual Development, most people diagnosed with ADD/ADHD are farsighted.
Normal eye exams (i.e., the 20/20 test) may be able to detect people who are severely farsighted, but are not as successful as with identifying mild to moderate farsightedness. It’s important for young children who may be farsighted to get routine examinations by a vision care professional.
Astigmatism is another common vision problem caused by an error in the shape of the eye.
In astigmatism, there is an irregular curve in either the lens of the eye or the cornea. Like nearsightedness and farsightedness, the irregular curve distorts the way that light is refracted into the retina. This blurs the images that you see once the brain has processed this information from the ocular nerve.
Astigmatism is different from nearsightedness and farsightedness because they are not associated with blurriness of vision at a specific distance. Rather, astigmatism can contribute to experiencing more general blurriness of vision.
Unlike myopia and hyperopia, astigmatism may develop from injuries or surgeries involving your eye.
There is no such thing as ”normal” vision. Every individual has particular genetic, behavioral, and lifestyle factors that contribute to how well they can see at any given time. Your own vision can even change throughout the day based on these same factors.
The typical standard used to assess vision clinically is 20/20 vision, typically measured using a visual acuity test. This means that you can clearly see at 20 feet what healthy eyes can see at that distance.
If you have 20/50 vision, for instance, it means that you must be 20 feet away from an object that someone with ”normal vision” can see from 50 feet.
Conditions like nearsightedness and farsightedness typically need correction with glasses, contacts, or laser eye surgery because the eye does not normally correct its shape on its own. Glasses and contacts help the eye refract light correctly, while laser eye surgery physically corrects nearsightedness, farsightedness, and astigmatism.
If you are experiencing blurry vision daily, visit an eye care professional.
Nearsightedness
Nearsightedness is diagnosed with visual acuity assessment tests. In these tests, you are tasked with reading letters from a chart at a specific distance.
If diagnosed, further testing will be required to determine your corrective prescription.
Farsightedness
As mentioned above, it can be difficult to detect mild to low cases of farsightedness.
Most cases can be detected with a refraction assessment and an eye health exam, which may include dilation of the pupils.
Astigmatism
Astigmatism can be diagnosed with visual acuity assessment tests, refraction tests, and keratometry.
How to help prevent visual impairment
While visual impairment can be inherited, here’s what you can do to limit your risk of myopia and hyperopia.
- Eat healthy foods like dark leafy greens and fish that are high in omega-3 fatty acids.
- Stay physically active to limit your risk of health conditions that lead to eye problems, like diabetes, high blood pressure, and high cholesterol.
- Give your eyes rest throughout the day. Take a break every 20 minutes to look at something roughly 20 feet away for 20 seconds.
- Wear sunglasses. Your eyes are susceptible to damage by UVA and UVB radiation.
- Quit smoking. Smoking increases the risk of diseases like macular degeneration and cataracts.
Depending on the severity of your condition, you may be able to go about daily tasks without treatment.
That being said, confirm with a healthcare professional that you‘re safe to perform activities like driving a vehicle or operating heavy machinery with impaired vision. These activities can be dangerous with visual impairments, and you also may not notice the eye fatigue and headaches that you’re experiencing as a result of your mild symptoms.
Most cases of nearsightedness, farsightedness, and astigmatism should be treated by a doctor with contact lenses, glasses, or surgery.
If you have moderate nearsightedness, farsightedness, or astigmatism it is beneficial to be treated with glasses. With glasses, you have control over how often you need your vision to be corrected. For more severe cases, you may want to consider surgery like laser eye surgery.
Nearsightedness means being able to see objects that are close, and farsightedness means being able to properly see objects that are far away. Astigmatism may contribute to nearsightedness and farsightedness, or may exist in your eye separately.
If you think that you have vision problems, see an optometrist or ophthalmologist to be professionally evaluated. They should be able to treat your symptoms with glasses, contacts, or surgery.
To help maintain eye health as you age, protect your eyes from the environment, eat healthy foods, and stay physically active.