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Blurred vision is a symptom, not a diagnosis. It may come from a common focusing problem or dry eye, but it can also be a sign of an eye condition that needs prompt assessment.
Useful details include whether the change began suddenly or gradually, affects one or both eyes, is constant or intermittent, and comes with pain, redness, flashes, floaters or a missing area of vision.
Common causes of blurred vision
- Refractive error: Short-sightedness, long-sightedness, astigmatism and age-related difficulty focusing up close can all make vision unclear.
- Dry eye: An unstable tear film may cause burning, grittiness, redness or vision that clears temporarily after blinking.
- Cataract: Gradual clouding of the natural lens can cause blur, glare, halos and faded colours.
- Diabetes-related eye disease: Diabetic retinopathy may have no early symptoms, while later changes can include blur or floating spots.
- Retinal, corneal or optic-nerve conditions: These have different causes and treatments and cannot be distinguished safely from symptoms alone.
When does blurred vision need urgent assessment?
Seek urgent medical assessment if blurred vision is accompanied by any of the following:
- Sudden loss or marked reduction of vision in one or both eyes.
- A sudden shower of new floaters, flashes of light, or a dark curtain or shadow across the vision.
- Severe eye pain, a red eye, halos around lights, headache, nausea or vomiting.
- Blurred vision after an eye injury, chemical exposure or recent eye surgery.
- Facial weakness, difficulty speaking, loss of balance, confusion or a sudden severe headache.
Do not drive yourself if your vision changes suddenly or significantly. Arrange urgent help and assessment instead.
How is the cause assessed?
The examination starts with the history of the symptom and measurement of vision. Depending on the findings, it may include refraction, slit-lamp examination, eye-pressure measurement and a dilated retinal and optic-nerve examination. Additional imaging or tests are selected only when needed.
Treatment depends on the cause. A new glasses prescription may solve a refractive problem, while dry eye, cataract, diabetes-related changes or retinal disease require different care plans.
What should you note before the examination?
- When the blur began and whether it was sudden or gradual.
- Whether it affects one eye or both.
- Any pain, redness, headache, flashes, floaters or double vision.
- Your medicines, medical conditions, recent injuries and any previous eye operations.
Avoid using someone else's eye drops or delaying assessment because the blur temporarily improves. The examination—not the symptom alone—determines the appropriate next step.