Blurred vision: possible causes and what to do

Questions about Blurred vision

Each answer below is the short version; the question links to the page that carries it in full, with sources.

• Why is my vision blurry?

  Blurred vision most often comes from an uncorrected or changed refractive error, a dry eye surface, or a problem with the lens, retina or optic nerve. Which one it is cannot be established from the symptom alone.

• Why is my vision blurry at night?

  Vision is commonly worse in low light because the pupil widens, which allows more peripheral light through and makes any refractive error more noticeable. Night blur can also relate to dryness, cataract or an irregular corneal surface.

• Why is only one eye blurry?

  Blur in one eye suggests something specific to that eye, such as a refractive difference, a surface problem, or an issue with the lens, retina or optic nerve on that side. It is worth an examination rather than a wait.

• Why do I wake up with blurry vision?

  Blur on waking is often a tear film problem, because the eye produces less tear overnight and the surface takes a few blinks to stabilise. It can also relate to a contact lens worn overnight, which is a reason to avoid that wherever possible.

• Is blurry vision normal after laser eye surgery?

  Some blur is expected early and can come and go for weeks. Blur that is getting progressively worse, that is accompanied by pain, or that appears suddenly later on is not something to wait out.

• Can LASIK vision become blurry again?

  Yes, it can, and the usual causes are a small regression in prescription, dry eye affecting the quality of the surface, or the onset of presbyopia. Blur that returns should be assessed rather than assumed to be one of these.

• Can vision become blurry after PRK?

  Blur immediately after PRK is expected, and it can take longer to settle than after flap procedures. Blur that appears or worsens months later is a different matter and should be assessed.

• Why do headlights look like halos or cause glare?

  Halos and glare around bright lights at night can come from corneal irregularities, cataract, dryness, an uncorrected astigmatism, or the healing phase after refractive surgery. They are a symptom, not a diagnosis.

• Why do I see floaters?

  Floaters are small opacities in the gel inside the eye that cast shadows on the retina. Many people have some, and longstanding floaters that are not changing are usually not an emergency.

• Why has my vision suddenly changed?

  A sudden change in vision needs urgent assessment rather than an appointment in a few weeks. It can be caused by something on the retina, a vascular event or an acute problem in the eye, and the timing matters for treatment.

• Why do my eyes feel tired and strained?

  Eye strain usually comes from sustained effort at a close task, often with an uncorrected or changed prescription, an unstable tear film, or prolonged focus without breaks. It is uncomfortable rather than damaging.

• Why am I seeing double?

  Double vision has two broad causes: a problem in one eye, or a failure of the two eyes to align. Both need assessment, and sudden double vision needs it urgently rather than routinely.