What causes sudden blurred vision or a sudden decline in visual acuity?

Sudden onset of blurred or decreased vision is commonly caused by visual impairment. It may also stem from glaucoma, cataracts, or diabetic retinopathy. So, what exactly causes sudden blurred vision? Below, we address this question.

What Causes Sudden Blurred Vision?

1. Diabetes

Diabetes can cause blurred vision. If a patient experiences blurriness, ocular edema, conjunctival hyperemia, or even retinal detachment, diabetic retinopathy may be the underlying cause. Diabetic retinopathy is the most severe ocular complication of diabetes. Patients with diabetes should strictly control their blood glucose levels and undergo regular fundus examinations.

2. Cataracts

Cataracts can lead to blurred vision, particularly in older adults. Affected individuals often describe their vision as if looking through a transparent film, resulting in diminished clarity. Additionally, elevated intraocular pressure and certain ocular inflammatory conditions—including keratitis, retinitis, and keratic stromatitis—can also cause blurred vision.

3. Glaucoma

Glaucoma can cause blurred vision due to elevated intraocular pressure. Increased intraocular pressure commonly leads to visual blurring. In addition to blurred vision, patients often experience ocular pain, varying degrees of visual loss, and ipsilateral headache.

4. Optic Neuropathy

Optic neuritis is a common form of optic neuropathy. Patients typically present with sudden vision loss accompanied by eye pain and delayed or absent pupillary light reflexes. Fundoscopic examination may reveal classic signs of papillitis, including optic disc hyperemia and swelling, visible physiological cupping, peripapillary retinal edema and clouding, flame-shaped hemorrhages, or yellowish-white exudates. Optic atrophy may also occur.

The above outlines potential causes of sudden blurred vision. Additionally, prolonged use of electronic devices—such as computers, televisions, and smartphones—reduces blink frequency and prolongs tear film evaporation time, leading to dryness and blurriness of the eyes. We hope this information is helpful to you.