Eye Health Central

Blurred Vision, Causes and Treatment

My Vision Is Blurry

Hazy, blurred, or unfocused vision can be caused by many different conditions or diseases. People with blurry vision often have to squint in order to see clearly, and even then it may only make their sight slightly better than it is without squinting. In many cases of blurred vision corrective lenses are all that is needed to fully correct the vision, such as contact lenses or eyeglasses, other times, the cause of the blurring may not be a simple refractory issue, and might require medication or surgery, or may not be correctable at all. 

Blurry vision may not affect both eyes equally, one eye could have perfect vision whilst the other is blurry,. Each eye is an individual and may experience blurred vision for two totally different reasons, and may need to be corrected with different methods. 

Why Is My Vision Blurry?

What Causes Blurred Vision?

Blurred vision can be a simple case of needing glasses or contact lenses or something easily treatable like dry eyes, but there are definitely conditions that need medical treatment such as glaucoma, that can also cause blurred or hazy vision. Here our optometrist sets out to help you differentiate between the mundane and the more serious, but blurred vision should always be checked out by an Optometrist or medical practitioner. 

Refractive Errors Causing Blurred Vision

For a large majority of people with blurry vision, the issue is a refractive error, meaning that the lenses in the front of the eye aren't accurately focusing light on the retina at the back of the eye. This is similar to holding a magnifying glass too close or too far away from an object or text. Finding the sweet spot brings everything into focus, which is what happens when we squint. The muscles around the eye squeeze and reshape the eye to bring the lens closer to, or farther from, the retina. A routine eye exam is the best way of diagnosing these types of vision problems.

There are several different kinds of refractive errors, each with similar but distinct symptoms, as well as their own means of correction.

  • Myopia – Commonly called near-sightedness or short-sighted, and occurs when light is focused in front of the retina. With this condition, things nearby appear clear and in focus but become increasingly blurry as the distance between the object and the eye increases. Corrective lenses can be used to refract light and move its focal point backward, placing it directly on the retina.
  • Hyperopia – Also known as far-sightedness or long-sighted, which is the opposite of myopia. Vision becomes blurry the closer an object gets to the eyes, as the light's focal point is behind the retina. This is less common, but just as easily solved with corrective lenses.
  • Astigmatism – This issue can be experienced in conjunction with myopia and hyperopia. It is a condition in which the eye is shaped irregularly, similar to an egg, rather than a sphere. By itself, it can cause mild double vision, but this may be hard to notice alongside other refractive errors. This can also be corrected with contact lenses or glasses, but they need to be specially designed to treat astigmatism, as regular lenses will not correct the astigmatism.
  • Presbyopia – A condition that affects many people as they age, usually starting in the 40s or 50s. Like astigmatism, this can occur on its own or alongside other vision problems. However, unlike the issues listed above, this is not caused by an irregular shape of the eye or its lens, but by the weakening of the muscles around the eye that are responsible for focusing light. Simple reading glasses can correct the issue, but when other refractory problems exist simultaneously, multifocal lenses may be needed to correct them all at once.

Temporary Causes of Blurred Vision

Other causes of blurry vision may not be as chronic as refractory errors, and may only last a few minutes, days, weeks, or possibly several months. Corrective lenses won't be an effective treatment, however, that doesn't mean that no treatment is available. Below are some of the varied non-refractive causes of blurred vision, and the best way of addressing them.

  • Dry Eyes – Some people suffer chronically from dry eyes, while others only experience it for brief periods. In either scenario, the eyes aren't well lubricated, which can lead to irritation and discomfort, as well as blurred vision. If the surface of the cornea becomes too dry, it may not allow light to pass through cleanly and might cause a blurring effect. Simple rewetting eye drops and/or good hydration are usually enough to solve this issue.

  • Pregnancy – There are many changes that happen throughout the body during pregnancy, and a change in visual acuity is only one of them, as is double vision. They are both caused by shifts in hormone levels, which then affect the shape of the cornea. While they aren't usually anything to worry about, it's important to bring changes in visual acuity to your doctor's attention, as there is a small change they could be signs of gestational diabetes or high blood pressure.

  • Headaches or Migraines – Even brief headaches or migraines can affect the muscles that focus the eyes, as well as cause serious and debilitating sensitivity to light. Fortunately, they usually don't last very long, but if they persist or happen frequently, you should see a doctor.

  • Floaters – Caused by microscopic bits of tissue or microbes moving within the gel-like fluid within the eye, floaters momentarily block light from passing through the eye, and cast a very tiny shadow on the retina. They typically only last a few seconds at a time and can be moved by quickly looking right and left, or up and down. If they begin to happen frequently, or in abundance, they may be early signs of a detached retina, which requires immediate medical treatment to avoid vision loss.

  • Medications – Some medications and medicated eye drops can affect vision, either by weakening the muscles that focus the eye, or by depositing chemicals or substances on the surface of the cornea. This can sometimes be treated with eye drops, but consult with your doctor first to make sure they won't interfere with the medication.

  • Laser Eye Surgery – You may experience blurred vision immediately following any type of eye surgery as the eye begins to heal. This is common and nothing to worry about unless it persists for more than a few days or is associated with pain. Consult with your eye doctor if you still have blurred vision after a few days.

  • Allergies – Seasonal or environmental allergies can affect the eyes, making them feel itchy, watery, and appear red. Taking allergy medications can be helpful, or simply removing the allergen from the environment. For pollen that may be difficult to achieve, but allergies to food, animals, or hygiene products are far more manageable.

  • Foreign Objects – Simply getting a bit of dust, dirt, or hair in your eye can cause not just blurred vision, but serious discomfort as well. Never rub your eye if it feels like there's something in it, as this may press it into the surface and cause serious scratching, as well as infection. Attempt to flush the foreign object out with eye wash, or clean water if none is available. If the feeling persists, seek medical attention quickly.

  • Contact Lenses – Under normal circumstances, contact lenses should only make vision clearer, not blurry. However, if the contact lens isn't seated properly, hasn't been cleaned well, or has been worn for too long, they can make it more difficult to see. Either rinsing the lenses with a cleaning solution or changing them out for a new pair should solve the problem, as well as giving your eyes a rest for several hours.

Possible Medical Reasons For Blurred Vision

In rare cases, blurry vision may be a symptom of a more serious underlying condition. If you are experiencing any of the symptoms below, you should make an appointment with your doctor quickly, as some of these problems can be very serious, and potentially lead to either blindness, or even death.

  • Cataracts – If vision is blurred and begins to appear cloudy, along with glare, or night halos, then you may be developing cataracts. They can be treated, usually with artificial lenses, but can severely limit vision if left unchecked. Cataracts are very common in older people but can occur at any age even at birth.

  • Glaucoma – Blurry tunnel vision may indicate the onset of glaucoma. These symptoms may develop slowly over time, or may occur suddenly. Without treatment, glaucoma will continue to worsen until all vision is lost, however, it can be alleviated with proper medical treatment.

  • Macular Degeneration – One of the most common causes of blindness in older people around the world, macular degeneration causes not only blurred vision, but a distortion of lines and images, and primarily affects the centre of the field of view, spreading outward over time.

  • Diabetic Retinopathy – Type 1 and tye 2 diabetes can lead to many other problems and conditions, one of which affects the eyes. Any diabetics who begin to have blurred vision should see a doctor or optometrist immediately to check for diabetic retinopathy which is a serious condition that can lead to loss of vision.

  • Systemic Issues – Strokes, heart disease, brain hemorrhages, and even multiple sclerosis all share a common symptom, which is blurred vision. While each of these conditions has many other symptoms that appear alongside diminished visual acuity, it's important to seek emergency medical attention should any of them arise. These can be life-threatening conditions, where just minutes can make the difference between life and death. 

If you experience blurred or cloudy vision and there is no obvious cause that you can eliminate, you should see an optometrist or your family doctor to check your vision and health.

Author: John Dreyer Optometrist Bsc(Hons), MCOPTOM, DipCLP
Created: 19 Feb 2024, Last modified: 20 May 2024