The most common causes of sudden blurred vision range from minor issues like dry eyes, eye strain, or sudden changes in refractive errors (glasses prescription) to more serious conditions like migraines, eye infections, diabetic fluctuations, or even emergency events like a stroke or TIA (mini-stroke), requiring immediate medical help. While often temporary, sudden blurriness needs prompt assessment to rule out severe causes, especially if accompanied by other symptoms like confusion, weakness, or severe headache, as highlighted by The Fred Hollows Foundation and Healthdirect.
What causes blurred vision to begin suddenly?
Diabetic drugs like metformin can cause blurry vision, too. Many times, metformin is the first medicine prescribed to someone with type 2 diabetes. Blurred eyesight is a relatively common side effect, but you should still tell your doctor if you experience it.
Hormones that support your developing fetus cause fluid retention. This extra fluid changes your eyes in ways that may result in blurry vision. They include: Changes to the shape or thickness of your corneas.
Cloudy vision can also be a result of changes in or damage to the cornea, (the clear bit at the front of your eye) including infections or inflammations. Less common conditions that may contribute to cloudy vision include: diabetes, optic nerve disease and macular degeneration.
Symptoms of neuromyelitis optica are related to the inflammation that occurs in the nerves of the eye and spinal cord. Vision changes caused by NMO are called optic neuritis. These may include: Blurred vision or loss of vision in one or both eyes.
It's common to experience blurred vision — when you can't see fine or focused details — in the form of nearsightedness or farsightedness. Seek medical care, however, if you experience a quick change in vision, such as a sudden loss of sharp vision.
If your blood sugar levels change quickly from low to normal, the shape of your eye's lens can be affected and your vision can be blurred. Your vision goes back to normal after your blood sugar stabilizes.
Vision changes are one of the most serious symptoms of preeclampsia. They may be associated with central nervous system irritation or be an indication of swelling of the brain (cerebral edema). Common vision changes include sensations of flashing lights, auras, light sensitivity, or blurry vision or spots.
For those that do, some of the first signs of preeclampsia are high blood pressure, protein in your pee and retaining water (this can cause weight gain and swelling). Other signs of preeclampsia include: Headaches. Blurry vision or light sensitivity.
Common side effects
Symptoms can include: Blurry or wavy vision in the center of your field of vision. Floaters. Noticing colors appear faded or washed out.
Cautions with other medicines
Common Causes of Transient Cloudy Vision
Dry Eyes: A lack of adequate tear production or improper tear film can cause the eyes to feel dry and contribute to transient cloudy vision. Migraine Headaches: Migraines, particularly the aura phase, can trigger visual disturbances, including transient cloudy vision.
Some blood pressure medications like beta-blockers and diuretics can decrease tear production. This can contribute to dry eye symptoms like burning or blurred vision, which are usually manageable with simple treatments like artificial tears.
Blurred vision has been reported as a symptom by patients with COVID-19. COVID-19 is known to cause several other eye problems, including dryness, redness, and sensitivity to light. Blurred vision can cause patients to experience other symptoms, such as headaches, dizziness, and difficulty concentrating.
HELLP syndrome is a rare liver and blood clotting disorder that can affect pregnant women. It's most likely to occur immediately after the baby is delivered, but can appear any time after 20 weeks of pregnancy, and in rare cases before 20 weeks.
The signs of hypertensive retinopathy include constricted and tortuous arterioles, retinal hemorrhage (Figure 1, 2, and 3), hard exudates (Figure 2), cotton-wool spots (Figure 1 and 3), retinal edema, and papilledema (Figure 3).
For many years pre eclampsia has been considered to be a two-stage disease. The first stage comprises poor placentation. The second stage is the clinical expression of the disease namely new hypertension and new proteinuria.
Five key signs your blood sugar (glucose) is too low (hypoglycemia) include feeling shaky/weak, sweaty/pale, dizzy/lightheaded, experiencing a fast or pounding heartbeat, and having trouble concentrating, feeling irritable, or suddenly very hungry, all signaling the body needs quick energy.
If your blood glucose stays high over time, it can damage the tiny blood vessels in the back of your eyes. This damage can begin during prediabetes, when blood glucose is higher than normal, but not high enough for you to be diagnosed with diabetes.
Medical conditions that can cause blurred vision include:
Blurry vision becomes a medical emergency when it appears suddenly, affects one eye, or is accompanied by other concerning symptoms. Seek immediate medical attention if you experience: Sudden vision loss in one or both eyes. Blurry vision with eye pain, redness, or sensitivity to light.
A transient ischemic attack (TIA), often called a mini-stroke, occurs when blood flow to the brain is temporarily blocked. If a TIA affects areas responsible for vision — such as the eyes or the visual processing centers in the brain — it can cause sudden vision loss, double vision, or blurry vision.
The 10-10-10 rule for eyes is a simple strategy to combat digital eye strain: every 10 minutes, take a 10-second break and look at something at least 10 feet away, giving your eyes a rest from near-focus on screens. This practice helps prevent eye fatigue, dryness, and headaches by allowing eye muscles to relax and encouraging blinking, which is often reduced during screen use, says Healthline and Brinton Vision.