Experiencing sudden blurred vision can be unsettling, especially when it occurs without warning. You might notice that words on a screen become unclear, objects appear hazy, or your surroundings seem out of focus.
Whether it affects one or both eyes, sudden changes in clarity often signal that something within the eye, or even the body, needs attention.
This article explores the potential causes, related symptoms, and the importance of obtaining a precise diagnosis.
What Sudden Blurred Vision Means
Sudden blurred vision is a rapid change in eye light, during which images become unclear or hazy. It can affect one or both eyes and may appear suddenly without warning. This visual change can interfere with central vision, reading, driving, or recognising faces.
Why Vision Can Suddenly Become Blurry
There are many possible reasons for sudden blurry vision, ranging from minor eye strain to more serious underlying health concerns. Understanding the cause of blurred vision helps determine whether it needs urgent medical attention.
Common Short-Term Causes
Sometimes, hazy vision may result from temporary issues like tired eyes or prolonged screen exposure. These causes often improve with rest or artificial tears.
Dry Eyes and Contact Lens Use
Wearing contacts for long periods or sleeping in them may reduce oxygen flow to the cornea. This can cause the eyes to become dry, irritated, or blurry. Maintaining proper lens hygiene and following your eye doctor’s recommendations helps reduce discomfort.
Refractive Errors and Focus Problems
Sudden changes in refractive errors, such as short-sightedness, long-sightedness, or astigmatism, can cause vision to be blurry. These occur when light entering the eye does not focus on the retina as it should, leading to visual disturbances.
When Blood Flow Affects Vision
Reduced blood flow to the eyes may result in sudden vision changes if the blood vessels supplying the retina or optic nerve become blocked or narrowed. Such changes require prompt medical attention to prevent further complications.
Low Blood Sugar and Vision
People with diabetes or insulin-related issues may experience sudden blurred vision due to low blood sugar levels. Fluctuations in glucose can affect the eye’s lens, altering its focus.
Optic Nerve and Inflammation
The optic nerve transmits visual signals from the eye to the brain. Inflammation, known as optic neuritis, can cause sudden vision loss or double vision. This condition may also produce pain when moving the eyes.
Central Vision and Macular Degeneration
Macular degeneration affects the part of the retina responsible for central vision. While it often develops gradually, sudden changes can occur if bleeding or swelling develops beneath the retina.
Eye Infections and Inflammation
Certain eye infections may cause blurry vision and other symptoms such as redness, discharge, or swelling. Prompt medical help and prescribed eye drops can help manage infections and prevent further complications.
Cloudy Vision and Cataracts
Cloudy vision can occur when the eye’s natural lens becomes less clear, often due to cataracts. While cataracts typically progress slowly, in rare cases, sudden blurring can occur if swelling develops within the lens.
Sudden Vision and Medical Emergencies
In some cases, the sudden onset of blurriness may signal a medical emergency. If vision suddenly becomes dark, distorted, or disappears entirely, seek immediate medical attention.
Warning Signs to Watch For
Certain other symptoms may accompany sudden blurred vision, including:
- Flashing lights or floating spots
- Double vision or shadowed images
- Difficulty speaking or facial weakness
- Loss of vision in one eye
If any of these occur, it is advisable to contact a healthcare provider without delay.
Understanding Visual Field Changes
A narrowing or loss in your visual field may occur alongside sudden blurry vision. This could indicate retinal or neurological issues requiring further examination.
When Vision Loss Occurs
Sudden vision loss should always be treated seriously. It may indicate a blockage or damage to the optic nerve or blood vessels supplying the eye. Prompt evaluation helps guide the next steps.
Frequently Asked Questions
Can dehydration cause blurred vision?
Yes, dehydration can reduce tear production and cause temporary hazy vision. Rehydrating and using artificial tears may help in mild cases.
Can high blood pressure affect my eyesight?
Yes. High blood pressure can damage retinal blood vessels, leading to blurry eyesight or changes in the visual field over time.
How can I protect my eyes from sudden vision changes?
Regular eye check-ups, managing health conditions, and remembering to wear eye protection can help maintain good visual health.
Conclusion
Sudden blurred vision can have many potential causes, from temporary irritation to conditions that need urgent care. Recognising the other symptoms, maintaining eye health, and seeking prompt medical help when necessary can support clear, stable sight.
If your vision is blurry or you’ve noticed recent changes in your vision, it’s important not to ignore them. Our team is here to provide guidance, assessment, and care tailored to your needs.
Contact Eye Laser Specialists at 03 9070 5788 or 03 9070 0910 to schedule an eye examination or consultation. Early attention can help keep your eyes healthy and your vision clear.
Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.
References
Ansorge, R. (2023, February 21). Simple Tips to Prevent Eye Fatigue. WebMD. Retrieved October 29, 2025, from https://www.webmd.com/eye-health/eye-fatigue-causes-symptoms-treatment
Felman, A. (2023, July 24). What Is the Connection Between Dry Eyes and Blurry Vision? Medical News Today. Retrieved October 29, 2025, from https://www.medicalnewstoday.com/articles/dry-eyes-and-blurry-vision
Lipner, M. (2025, August 18). What Causes Sudden Blurry Vision? Verywell Health. Retrieved October 29, 2025, from https://www.verywellhealth.com/sudden-blurry-vision-5092267
