Updated on 

October 25, 2021

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Trouble Focusing Eyes

What is it Called When Your Eyes Have Trouble Focusing?

When your eyes have trouble focusing, they often lose the sharpness of your eyesight. Objects may appear out of focus and hazy. 

Blurred vision can affect both eyes. However, some people experience issues in one eye only.

Cloudy vision, in which objects appear ‘milky’ and obscured, is very similar to blurry vision. However, cloudy vision is usually a symptom of certain conditions such as cataracts.

Trouble Focusing Eyes

The main causes of a blurred field of vision are refractive errors, including astigmatism and presbyopia. However, vision health problems can also be a symptom of more severe issues, including potentially sight-threatening eye diseases. Blurry vision and cloudy vision can be symptoms of a severe eye condition, especially if they occur suddenly.

If you have blurry vision and you are unsure what is causing it, visit an optician or eye doctor for a comprehensive eye examination.

Common Causes of Eye Focusing Problems

Here are some common causes of eye health problems like blurry vision:

Computer Vision Syndrome

If you spend significant periods using a computer screen or watching television, your eyes can become tired. This tiredness can lead to a blurry field of vision. 

Using a computer or watching television does not cause permanent damage to your eye health. However, using a computer screen or staring at television is a demanding visual system task that can lead to eye discomfort.

If you have an uncorrected vision issue, this can make screen use uncomfortable. It can also lead to blurry vision and strain. 

Whenever you concentrate on watching a screen, you tend to blink less. This can lead to dry eyes. If you are in a dry environment, like a heated or air-conditioned office, this eye dryness can worsen.

You can prevent dry eyes and reduce the risk of tired or strained eyes while using or watching a screen. Be sure to take regular breaks and look at objects that are at varying distances. Make an effort to blink often, too.


Your eye focuses light using the cornea and the lens. The cornea is the transparent ‘window’ at the front of the eye. The lens is inside the eye.

The cornea does the most focus. If it has a standard curved form, like a soccer ball, then the light is focused effectively. But if the cornea has an abnormal curve, like a rugby ball, the light is focused unevenly, and the vision is blurry. This is known as astigmatism.

astigmatism sphere

Most people have astigmatism, but the condition varies between individuals. The more your cornea is formed like a rugby ball, the worse your vision will be. Rarely, astigmatism is caused by other factors, such as abnormalities of the lens or issues from a lens implant.

Astigmatism can be challenging to treat. However, there is a range of procedures to improve the condition. Treatments include laser refractive surgery to adjust the shape of the cornea. Patients can also opt for lens implants with an astigmatic correction.


Presbyopia is a common eye condition that makes vision challenging at a typical reading distance. For example, you may find that you are keeping your book further away from your eyes to read the text clearer. Or, when working close-up, you develop sore eyes, headaches, or fatigue.

As we age, the lens loses its flexibility and cannot adjust its shape and focus. This is a normal part of the aging process. Presbyopia is typically first noticed from 40 to 45 years and worsens between the ages of 45 and 65. From 65 years onwards, an individual’s presbyopia is unlikely to decline.

graphic showing normal eye and presbyopia

Presbyopia is treated with an eyeglasses prescription designed for close distances. Multifocals, bifocals, or half-glasses enable you to do close-up work and view distant objects. There are also contact lenses specially designed for presbyopia with monovision or multifocal designs. New laser and cataract surgery methods can also treat presbyopia. 

From the ages of 45 up to 65, your eyeglasses or contact lens prescription is likely to change. It is essential to have an eye examination at least every two to three years to review your correction and eye health.

Eye Strain

Eye strain can develop after looking at and focusing on something for extended periods without a break. This is called computer vision syndrome when concentrating on a digital device like a computer screen or television. Other causes include reading and driving, especially during the night and in bad weather. 

Corneal Abrasion

Your cornea is the transparent covering on the front of your eye. When it gets injured or scratched, you may develop corneal abrasion. Vision may become blurry, and it may feel like there is something in your eye.

Pink Eye

Otherwise known as conjunctivitis, pink eye is an infection of the outer lining of your eye. A virus typically causes it, but it can also result from the spread of bacteria.

High Blood Sugar

Extremely high blood sugar levels can cause the lens of your eye to swell. This can lead to blurred vision.

Age-Related Macular Degeneration 

Age-related macular degeneration is a leading cause of blindness among older people. The condition can often lead to blurry vision and visual distortions that cause straight lines to appear wavy or broken.

Macular Degeneration


Vision shifts, including blurred or cloudy vision, may be warning signs of cataracts. Cataracts are when the lens in your eye develops cloudy patches. Glare and halos around lights at night may also be warning signs of cataracts.


If left untreated, cataracts can worsen and potentially lead to blindness. Cataract surgery replaces cataracts with artificial lenses, which typically restores lost vision. 

Serious Causes of Sudden Vision Changes (Require Immediate Attention)

Some causes of sudden vision changes are medical emergencies that must be treated as soon as possible to prevent permanent loss of vision and damage.


Blurry or lost vision in both eyes can occur when you experience a stroke affecting your brain's area that controls vision. A stroke involving your eyes leads to blurred or lost vision in just one eye. You may also have other symptoms of a stroke, including some weakness on one side of your body or the inability to speak.

Detached Retina 

A detached retina occurs when your retina detaches from the back of your eye and loses its blood and nerve supply. When this happens, you may see black spots or flashes of light, followed by blurred or absent vision. 

Without emergency treatment, permanent vision loss may occur. 

Transient Ischemic Attack (TIAs)

A transient ischemic attack (TIA) is a stroke lasting less than 24 hours. One of its symptoms may be a blurred vision in one or both eyes.

Other Symptoms Associated With Blurred Vision

Along with sudden blurred vision, you may experience other eye symptoms that range from mild to severe. These eye symptoms include:

  • Light sensitivity, or photophobia
  • Pain redness
  • Double vision
  • Floating specks in front of your eyes, known as floaters

Treatment For Sudden Blurry Vision 

Treatment for sudden blurry vision depends on the condition affecting your eyesight.

Not all causes of sudden blurry vision require urgent medical treatment. However, if you have sudden blurry vision and you think you may be having a stroke, are experiencing severe eye pain, or think you may have a detached retina, it is essential to call 911.

If you have unexplained sudden blurry vision, seek medical advice from a healthcare provider, ophthalmologist, or optometrist as soon as possible, even if it has passed.

Read More: How to Improve Your Eyesight

6 Cited Research Articles
  1. Warning signs of a serious eye problem, Harvard Health Publishing, https://www.health.harvard.edu/diseases-and-conditions/warning-signs-of-a-serious-eye-problem 
  2. Eyes - common problems, Better Health, April 2015, https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/eyes-common-problems 
  3. Keep an Eye on Your Vision Health, Centers for Disease Control and Prevention (CDC), October 2020, https://www.cdc.gov/visionhealth/resources/features/keep-eye-on-vision-health.html 
  4. Age-Related Macular Degeneration, National Eye Institute (NEI), August 2020, https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/age-related-macular-degeneration 
  5. Retinal Detachment, National Eye Institute (NEI), September 2020, https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/retinal-detachment 
  6. Stroke, Centers for Disease Control and Prevention (CDC), October 2020, https://www.cdc.gov/stroke/index.htm
Melody Huang is an optometrist and freelance health writer. Through her writing, Dr. Huang enjoys educating patients on how to lead healthier and happier lives. She also has an interest in Eastern medicine practices and learning about integrative medicine. When she’s not working, Dr. Huang loves reviewing new skin care products, trying interesting food recipes, or hanging with her adopted cats.
Ellie Swain earned her B.A. in Sociology from the University of Sussex in the United Kingdom. After working in digital marketing and copywriting after graduating, she transitioned to full-time freelance writing and editing. Ellie has a passion for social causes and writes regularly on issues of homelessness in which physical and mental health disorders are common among rough sleepers. She aims to create authoritative and research-backed content on addiction to encourage people to find the support and treatment they need.
Author: Ellie Swain  | UPDATED October 25, 2021
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Medical reviewer: Dr. Melody Huang, O.D.
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Dr. Melody Huang, O.D.
The information provided on VisionCenter.org should not be used in place of actual information provided by a doctor or a specialist.

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