Sudden blurring of vision can result from dry eye or from a singular incident, such as retinal detachment, stroke, or a transient ischemic attack (TIA). There are 18 known causes that can lead to abrupt changes in vision clarity, highlighting the urgency for prompt medical intervention to avert lasting damage to vision.
Here are 18 reasons why you might suddenly experience blurred vision.
Conditions That Require Immediate Medical Attention
Certain causes of sudden blurry vision are urgent medical conditions that need prompt treatment to avoid lasting harm and loss of sight.
1. Retinal Detachment
This condition occurs when the retina detaches from the back of the eye, cutting off its access to blood and nerves. The National Eye Institute notes that aging or injury often causes this, but diabetes can also lead to retinal detachment. Symptoms include seeing flashes or floaters, sometimes appearing dark or black, and a portion of your vision may become blurred or completely disappear, often likened to a curtain dropping over your eyesight. Without swift medical intervention, the loss of vision in the affected area could be irreversible.
2. Stroke
A stroke can lead to blurred or completely lost vision in both eyes if it affects the brain area responsible for vision. When the stroke specifically impacts the eye, it may result in blurred or lost vision in just one eye.
Additional symptoms accompanying a stroke may include:
- Drooping of one side of the face
- Weakness in the arms
- Trouble speaking
- Sudden numbness, particularly on one side of the body
- Immediate confusion
- Dizziness or loss of balance and coordination
- Intense headache without a clear reason
3. Transient Ischemic Attack (TIA)
A TIA, often described as a mini-stroke, is a temporary blockage of blood flow to the brain, lasting less than 24 hours. It can cause symptoms similar to a stroke, including blurred vision in one or both eyes, indicating an urgent need for medical evaluation to prevent a full-blown stroke.
4. Wet Macular Degeneration
This condition occurs when new, abnormal blood vessels grow under the macula, the central part of the retina responsible for detailed vision. These vessels can leak blood and fluid, leading to wet macular degeneration. It is characterized by sudden blurriness and loss of central vision. In contrast to the gradual onset of dry macular degeneration, the wet type can develop swiftly and worsen quickly, necessitating prompt medical attention to slow or halt vision loss.
5. Angle-Closure Glaucoma
This type of glaucoma develops when the eye’s drainage pathways are obstructed, leading to a rapid increase in intraocular pressure. Symptoms include eye redness, pain, and nausea, along with visual disturbances like seeing halos around lights. Angle-closure glaucoma is an urgent condition that necessitates immediate medical intervention, which may involve the use of eye drops, laser treatments, or surgery to alleviate the pressure and reduce inflammation.
6. Endophthalmitis
Endophthalmitis is a severe infection of the eye’s internal fluids, leading to significant inflammation. Signs of this critical condition include blurry vision, discharge of pus from the eye, and swollen or puffy eyelids. The infection typically follows eye surgery but can also result from an infection elsewhere in the body spreading to the eye. Prompt medical treatment is crucial to address this emergency situation.
7. Concussion
A concussion is considered a mild form of traumatic brain injury. Given that a large portion of the brain’s pathways are involved in vision and eye movement control, it’s common for brain injuries to lead to blurry vision. Although concussions typically don’t result in permanent vision damage or loss, they can occur alongside spinal injuries or a subdural hematoma. Therefore, immediate medical examination following a concussion is crucial.
Eye Infections
8. Conjunctivitis
Commonly known as pink eye, conjunctivitis is an inflammation of the eye’s outer lining. The condition is most often viral but can also stem from bacterial infections or allergies. Conjunctivitis is characterized by redness, itchiness, and a discharge from the eye, requiring appropriate treatment based on the underlying cause.
9. Keratitis
Keratitis refers to the inflammation of the cornea, often resulting from an infection. Risk factors for developing keratitis include prolonged use of the same pair of contact lenses, using improperly cleaned contacts, sleeping in contacts, or exposing contacts to water from swimming or tap water. Symptoms can include pain, redness, and impaired vision, necessitating prompt medical treatment.
10. Uveitis
Uveitis is the inflammation of the uvea, the eye’s middle layer that contains the iris and other pigmented structures. This condition can be triggered by an infection or an autoimmune response, leading to discomfort and pain in the eye. Iritis, inflammation of the iris, is the most frequent type of uveitis. While uveitis can manifest on its own, it may also be associated with systemic autoimmune diseases such as rheumatoid arthritis or sarcoidosis, or infections like herpes. Symptoms include pain, eye redness, blurred vision, and light sensitivity.
Other potential reasons for experiencing sudden blurred vision can include:
11. Dry Eye Syndrome
Sudden blurred vision can be a symptom of dry eye syndrome, which occurs when your eyes don’t produce sufficient tears or when tears evaporate too quickly. While blurred vision might be a standalone symptom, experiencing it alongside dry, itchy eyes could indicate an underlying health issue that requires medical attention.
12. Eyestrain
Eyestrain can result from prolonged focus on an object without adequate breaks, leading to reduced blinking and dry eyes. This is often experienced after extended periods of using digital devices, such as computers and smartphones, and is known as digital eyestrain. Reading and driving for long durations, especially under challenging conditions like at night or in bad weather, can also cause eyestrain.
13. Corneal Abrasion
A scratch or injury to the cornea, the clear front cover of the eye, results in a corneal abrasion. Symptoms include blurry vision and the sensation of having something in your eye, necessitating prompt medical evaluation and treatment to prevent infection and ensure healing.
14. High Blood Sugar and Diabetes-Related Effects
Elevated blood sugar levels can make the lens of your eye swell, leading to blurred vision. For individuals with diabetes, sudden changes in vision could indicate diabetic retinopathy, a condition requiring immediate attention from both diabetes care teams and eye health professionals.
15. Hyphema
Hyphema refers to the pooling of dark red blood inside the front part of the eyeball, resulting from an injury that causes bleeding. Besides causing blurred vision, a hyphema can lead to pain and increased pressure within the eye, which are signs that urgent medical care is needed.
16. Migraine with Aura
Migraine attacks may be preceded by an aura, a condition that can lead to blurred vision along with the appearance of wavy lines or flashing lights and other sensory disturbances. It’s possible to experience an aura without the accompanying headache, making this a unique and identifiable precursor to a migraine for some individuals.
17. Optic Neuritis
Optic neuritis involves inflammation of the optic nerve, which connects the eye to the brain. This condition is often triggered by an autoimmune response or is associated with multiple sclerosis, but it can also arise from other autoimmune diseases like lupus or from infections. Optic neuritis typically impacts just one eye and can significantly affect vision.
18. Temporal Arteritis
Also known as giant cell arteritis, temporal arteritis is an inflammation of the medium and large arteries, often affecting the arteries around the temples. This condition can lead to a pulsating headache in the forehead area and may also cause vision to become blurred or even temporarily lost, signaling the need for immediate medical intervention to prevent more severe complications.
