Want Clinically Backed Eye Care Tips FREE + $10 Off Coupon?

Yes, Sign me up!
Your Best Resource for Dry Eye and Macular Degeneration Education

What are the Causes of Blurred Vision?

Views: 3084
Reviewed by Nymark M, PhD on March 16, 2016

If you’re experiencing symptoms of blurred vision, then chances are that you’re having trouble seeing items and other people in fine detail. Sometimes, blurred vision can occur as a result of abnormalities that are present from birth, such as farsightedness or nearsightedness – conditions that require corrective lenses. On the other hand, blurred vision may signal the presence of an eye disease or injury, one common option being dry eye disease. Depending on the cause behind your condition, blurred vision can occur in both eyes, or just one, and it may be a symptom of numerous conditions that don’t include the eyes at all, such as a stroke or migraine. Various medications such as Restasis can also lead to temporary blurred vision as a side effect.

Symptoms of Blurred Vision

Sharp, clear vision is what helps us to navigate the world on a daily basis, assisting with everything from reading traffic signs to ensuring we don’t trip over an item in our home. Blurry vision on the other hand can affect your entire line of sight, or just small portions of your vision. Either way, you could end up feeling as though someone has put a filter over your eyes that makes it impossible to focus.

While the obvious symptoms of blurred vision or hazy or unfocused sight, it’s important to understand that blurred vision is a very general term that can apply to a range of different problems including:

  • General blurred vision – inability to see an image clearly – it’s important to establish whether the blurring occurs more at close distance, or when objects are further away.
  • Decreased peripheral vision – blurring may occur around the sides of a vision, leading patients to bump into items or have trouble parking.
  • Alteration of an image – sometimes blurring can cause images to appear smaller or larger, or even distorted.
  • Diplopia – this is when blurred vision causes double vision, when the eye is unable to focus on an item or image.
  • Dry eye blurring – this occurs when a dry eye is unable to focus on an item, leading to blurring and discomfort that can be temporarily reduced by blinking.

Causes of Blurred Vision

There can be various causes of blurry vision. For example, people may suffer from refractive errors that lead to conditions such as long-sightedness, and short-sightedness. Long sightedness causes blurring in the vision when a person views objects close up, such as when using a computer or reading a book. On the other hand, short-sightedness leads to blurred vision when an individual views objects at a distance, such as when watching television or driving. Crucially, astigmatism can cause blurred vision when an individual views an object from any distance.

Other causes of blurred vision include:

  • Cataracts – Cataracts occurs when the lens of the eye becomes cloudy due to a buildup of protein. Often, the initial blurring in these circumstances is difficult to notice, and may be almost imperceptible. However, over time cataracts can result in severe blurred vision and impact your comfort significantly.
  • Diabetic retinopathy – A condition associated with diabetes, diabetic retinopathy happens when high blood sugar levels cause damage in the retina, the surface utilized to help the eye focus on certain images. This condition can lead to macular edema, which leads to blurred vision.
  • Epiretinal membrane development – An epiretinal membrane is a fibrous, thin layer that can begin to grow over the retina. This film behaves like a filter that blocks the light entering the eye leading to the onset of blurred vision.
  • Keratoconus – A disease that results in a conically shaped cornea, keratoconus can affect the way the cornea focuses on images, leading to irregular or blurred vision.
  • Macular degeneration – the macula is the main part of the retina located at the rear of the eye. This system allows you to see clearly in color, noticing details in the things directly in front of you. Macular holes or macular degeneration cause damage to the macula which leads to blurring.
  • Retinal vein occlusion – If the blood vessels responsible for feeding the retina are blocked for some reason, this can cause a condition known as retinal vein occlusion, which results in suddenly blurred vision, and even sudden blindness in some cases.
  • Retinal detachment – a detached retina is a severe medical emergency that can lead to sudden blindness, blurred vision, and a number of other eye-related symptoms.
  • Pterygium – A pterygium is a type of benign growth that happens on the surface of the eye, and may sometimes occur in the cornea. When this happens, the shape of the cornea can be altered, which results in blurred vision.
  • Eye infection, injury, or inflammation – Many people experience blurred vision as a result of an eye injury or infection. Eyelash and eyelid problems can sometimes lead to blurred vision, as can common infections such as conjunctivitis.
  • Vitreous hemorrhage – If blood leaks into the gel that fills the eye, it can block out some of the light entering the eye, leading to blurred vision. This issue can occur as a result of an eye condition like diabetic retinopathy, or it may occur as a result of trauma.

Blurred Vision Caused by Dry Eye Syndrome

Dry eye disease, or dry eye syndrome, is a highly common condition that takes place when the eyes are unable to make the right amount of tears, or the tears in question do not have the right chemical makeup. When tears are insufficient, this leads to a dry sensation in the eye that can cause it to become irritated, inflamed, and often may result in blurry vision. This condition is known as keratoconjunctivitis sicca, and the symptoms involved typically affect both eyes, including issues such as: feelings of grittiness, soreness, or dryness that worsen throughout the day, red eyes, and eyelids that stick together.

One of the most common issues caused by dry eye syndrome is blurred vision, as the eye can struggle to focus light and images properly when the surface of the cornea is too dry. Fortunately, this isn’t considered to be a serious condition, and there are numerous treatments available that can help to relieve the symptoms, including the application of eye drops used to lubricate the eye, and the prescription of medication to reduce inflammation. In some cases of this syndrome, surgery may be recommended to help prevent tears from draining away too quickly. What’s more, if the issue is caused by an underlying condition, treating this problem generally helps to relieve the symptoms.

Diagnosing the Causes of Blurred Vision

Although blurred vision may not seem like a serious or significant condition, it’s important that you should never ignore the symptoms. In many cases, blurred vision may actually be a symptom of another underlying condition, which is why your doctor should be consulted as early as possible. To diagnose the cause of your blurred vision, your doctor may use a number of different examination procedures, including:

  • A refraction test – this test is designed to measure the prescription you could need for contact lenses or eyeglasses. A device known as a refractor or phoroptor will be used, and by looking through the device, you will be asked to focus on a Snellen eye chart. As your doctor asks for you to read the chart, they will also put lenses of different strengths in and out of your view to determine whether you are in need of a prescription.
  • Slit-lamp examination – To examine your eye using a slit lamp, your doctor will ask you to place your chin on a resting pad. During the examination, your eye doctor will utilize the machine to focus on various structures throughout the eye to discover whether or not the eye is functioning as it should. Where necessary, your doctor may adjust the level of magnification and light used to see better. During the examination, you will be given an anesthetic eye drop to help numb the surface of the eye, and you will also be given a drop called fluorescein, which will coat the eye and glow under blue lights if there is something abnormal on the surface of the eye.
  • Tonometry – During an examination by slit-lamp, your doctor may check your eyes for intraocular pressure. The fluorescein and anesthetic eye drops used will allow your doctor to measure your eye pressure using a device known as a tonometer, which will be attached to the slit lamp. During this procedure, your doctor will ask you to breathe normally and keep your eyes wide open.

Treating Blurred Vision

Determining the best treatment for your blurred vision will depend entirely on the factors that are causing the symptoms in the first place. For instance, refractive errors such as long-sightedness, astigmatism, and short-sightedness can be permanently corrected in some people through laser eye surgery. These conditions can also be improved with the use of prescription lenses and eyeglasses.

On the other hand, if your blurry vision has been caused by a decrease in blood sugar, then your treatment may be as simple as consuming foods that contain an adequate amount of fast-acting sugars. Treatments may include anything from laser surgery, to eye drops, medications, and other processes designed to control underlying conditions.

How to Prevent Blurry Vision

In certain circumstances, the onset of blurry vision is inevitable. However, in many cases, this can be prevented or corrected for most people. For example, ensuring that you wear sunglasses when outdoors on particularly sunny days will help to decrease your sensitivity to light, which could reduce your chances of suffering from temporary blurred vision. Another option is to avoid drinking alcohol whenever possible, as the consumption of alcohol can often alter vision.

Undergoing regular eye examinations is a particularly important part of maintaining good vision, particularly for people who are over the age of 65, or already suffer from an underlying condition such as high blood pressure or diabetes that might cause blurred vision. The following table should help you to determine when your next visit should be scheduled.

Age Frequency of Visit
0-6 months At least once a year
6 months to 18 years Every 2 to 4 years
19 years to 38 years At least every 3 to 5 years
40 years to 64 years At least every 2 to 4 years
Older than 65 Every year, or every 2 years

While preventing blurred vision isn’t always possible, taking careful steps to care for your eyes and maintaining good vision health will help to prevent some of the causes of blurred vision often related to lifestyle. For example:

  • Always wear broad-spectrum protective sunglasses when going outdoors on a sunny day.
  • Eat a diet that is high in eye-healthy nutrients such as omega-3 fatty acids.
  • Avoid smoking and drinking wherever possible
  • Frequently undergo regular eye examinations – particularly if you have a history of eye-related illnesses in your family or have had numerous eye problems in the past
  • Wash your hands thoroughly before taking out or putting in contacts to reduce your risk of infection.
  • Be sure to wear protective eyewear when you are operating heavy machinery or engaging in activities like home repairs or painting.

When to Speak to Your Doctor

If you’re concerned about symptoms of dry eye, or have been dealing with problems of blurred vision for an extended period of time, it may be worth contacting your doctor for a checkup at your earliest convenience. Keep in mind that if you are concerned a medication has caused the blurry vision, you shouldn’t switch or discontinue medications before you see your eye doctor.

If you are suffering from severe eye pain or the eye looks to be inflamed and red, make sure that you contact an eye doctor immediately.

Resources and References:

  • Blurred Vision – A basic guide to blurred vision signs and symptoms. (MedicineNet.com)
  • Eye health guide – A comprehensive guide to eye health and problems that may cause blurred vision. (WebMD)
  • Dry Eye Syndrome – A guide on the symptoms and signs of dry eye disease. (Healthline.com)
  • Blurry Vision in One Eye or Both Eyes – Information about blurry vision that occurs in one or both eyes. (All About Vision)