When our vision loses its clarity, we say that we have Blurry vision, at this time it becomes very difficult to see the details of the images and we will not be able to distinguish the boundaries of objects.


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When is blurring dangerous?

People with refractive errors such as farsightedness, myopia, and astigmatism, or who have difficulty adjusting due to presbyopia, may also have blurred vision.

But what can be a sign of a serious eye problem is a sudden loss of visual acuity. In the following, we will examine eye diseases that can cause loss of visual acuity


Various causes of blurred vision

Among the diseases and problems that can cause blurred vision, the following can be mentioned:

Detachment Retina (Retinal tear)

Diabetic retinopathy (Ocular complication due to diabetes)

Increased intracranial pressure

Optic neuritis

In the following, we will briefly explain these causes

Before explaining the reasons for the decrease in visual acuity, it is better to know a little about the structure and function of the retina.


Retinal membrane anatomy

The retina is the membrane behind our eyeball that is made up of light-sensitive cells. The optic nerve enters the retina from behind our eye. The place where the optic nerve enters and exits is called the (blind spot). This area does not have any light-sensitive cells.

Yellow spot

An area of ​​the retina called the yellow spot or macula is the area of ​​the eye that is most sensitive to light and is responsible for our clear vision. Many delicate and precise procedures such as sewing, surgery, etc. require a healthy macula. So any factor that damages the retina in any way, especially the macula, can impair our clear vision.


Eye involvement in diabetes and blurred vision

Diabetes causes a series of abnormal changes in the retina with effects on the walls of the blood vessels at the end of the eye, which we call “diabetic retinopathy”.

Diabetes with inflammation and changes in the walls of the arteries of the eye causes the strength of the walls of the arteries to be lost Consequently, fluid leakage, bleeding, and swelling occur in the retina. In the early stages of diabetic retinopathy, most patients are asymptomatic unless swelling and bleeding occur in the macula which can cause sudden loss of clear vision.

In advanced stages, clumps of abnormal new arteries form that cause blurred vision by causing swelling and bleeding. Detachment of the retinal layers due to diabetes, which is called “retinal detachment”, also suddenly causes blurry vision.


Retinal detachment and blurred vision (retinal detachment)

The retinal detachment from the surrounding layer is called retinal detachment which is considered as an eye emergency and in case of an emergency, it is necessary to go to an equipped medical center before the retinal detachment from the surrounding layer leads to a sudden blurry vision.

The following may be felt by the affected person

Light sparks in the visual field

Seeing thread-like objects in the field of view (floater)

The appearance of a black curtain in the center or around the field of view

Sometimes small cracks form in the retina before it completely separates from the surrounding layer. Through these cracks, the fluid in the space behind the lens and in front of the retina enters the sub retinal layer and gradually causes retinal detachment. These symptoms may also occur at the time of retinal rupture and the person is completely asymptomatic before

In either case, you should not delay seeing your eye doctor


People prone to retinal rupture

To avoid retinal detachment, it is recommended to see an ophthalmologist as soon as possible in case of exposure to light sparks or flutter in the field of vision.


Strokes and blurred vision

A sudden decrease in visual acuity can be one of the warning signs of a stroke.

Impaired blood flow to the visual cortex behind the brain or impaired blood flow to the optic nerve are some of the things that happen in the cerebral arteries that cause sudden blurry vision.

If you have any of the following severe symptoms with blurred vision, it is necessary to contact the emergency service:


Migraine and blurred vision

Migraine headaches can be associated with some vision problems. The vision changes that usually occur before a migraine attack are called “migraine vision auras” which include:


Multiple sclerosis and blurred vision

Inflammation around the optic nerve, called optic neuritis, is one of the primary symptoms in patients with multiple sclerosis.

In addition to loss of visual acuity in MS, the following symptoms may occur:

Note: Blurred vision is not always caused by MS. In other words, any factor that can lead to inflammation of the optic nerve will be associated with a sudden decrease in visual acuity, so it can only cause blurred vision if MS affects the optic nerve.


Brain tumors and blurred vision

Any space lesion inside the skull, such as extensive bleeding or tumors, will increase intracranial pressure. This increase in pressure can be accompanied by the following symptoms:

One of the secondary symptoms of increased intracranial pressure is a decrease in visual acuity that has not been seen before.


The final word

If you are pregnant, decreased vision can be a warning sign associated with increased gestational hypertension and preeclampsia (a dangerous complication in pregnant women that is associated with high blood pressure and liver, kidney, etc.).

Parkinson’s disease in advanced stages can sometimes be accompanied by ocular symptoms, but decreased visual acuity in the early stages of Parkinson’s disease is unlikely.