Why Does Your Vision Go Dark: Main Causes and What to Do

Many people know the feeling of wondering why their vision suddenly goes dark. It can come on abruptly for a few seconds, especially when changing body position. Sometimes it is accompanied by weakness or loss of balance, which causes anxiety and a sense of unsteadiness. It is important to understand that such symptoms can be harmless, but they can also be the body's signal of possible problems that should not be ignored.

Main reasons why your vision goes dark

Most often, vision going dark is linked to a brief disruption of blood supply to the brain. At such moments the visual system receives less oxygen, so the image darkens or blurs, sometimes with a feeling of unsteadiness.

This happens especially when you stand up quickly. That is why many people notice their vision going dark when getting out of bed or after sitting for a long time, especially in the morning or after resting. This is called an orthostatic reaction, and it usually passes quickly.

It is also worth bearing in mind that what causes your vision to go dark may depend on your general health, level of physical activity, tiredness and even your eating habits, so it is important to look at the situation as a whole.

Blurred vision and related symptoms

Sometimes patients describe not just darkening, but cloudy vision or a feeling of a film over the eyes. This may be accompanied by reduced sharpness, difficulty focusing and a brief worsening of how you see the image.

The causes range from overtiredness to more serious problems with the visual system. For example, long hours at the computer, stress or lack of sleep can cause temporary cloudy vision, which usually goes away after a proper rest and less strain on the eyes.

In some cases, floaters appear — dots, threads or small shadows that move as you move your eyes and are especially noticeable against a light background. They may be linked to age-related or structural changes in the vitreous body of the eye and need monitoring if they appear often.

When your vision goes dark and you feel dizzy

If your vision goes dark and you feel dizzy at the same time, this is a more pronounced symptom that deserves attention. It may point to problems with blood pressure, blood vessels or the nervous system, especially if such episodes recur.

Many people wonder what causes dizziness and darkening of vision, and the reasons can vary. The most common are:

• a sharp drop in blood pressure
• dehydration
• overtiredness and lack of sleep
• low blood sugar

If the condition keeps coming back and you regularly feel dizzy with your vision going dark, it is important not to ignore the symptom and to get diagnosed in good time to rule out serious problems.

It is worth noting separately that frequent dizziness with darkening of vision may be a sign of chronic problems related to blood vessels or metabolism, and in that case you need to be monitored by a specialist.

Diseases that cause darkening and cloudy vision

In some cases, darkening of vision is linked to diseases of various body systems, so it is important to consider this symptom not in isolation but together with your overall health.

The main causes include:

• cardiovascular disorders
• endocrine disorders
• anaemia and vitamin deficiencies
• diseases of the nervous system

It is also important to consider causes of cloudy vision that relate directly to vision and the structures of the eye. For example:

• raised intraocular pressure
• short-sightedness or long-sightedness
• changes in the lens

These causes may point to developing cataracts if your vision gradually gets worse and becomes more noticeably impaired over time.

Why your vision goes dark when you stand up

It is worth looking separately at darkening of vision when getting up from sitting or lying down, as this is one of the most common situations of this kind. It most often occurs because of a sudden redistribution of blood when the body changes position.

When you get up quickly, your blood vessels do not have time to adapt to the change in pressure, and the brain briefly lacks oxygen. As a result, your vision goes dark, and you may feel slightly dizzy and unsteady.

In most cases this is not dangerous and passes on its own, but if such episodes happen often or become more pronounced, it is worth checking your blood pressure, blood vessels and general health.

When to see a doctor

Vision going dark is not always harmless, so it is important to pay attention to such signals from your body. There are a number of signs that call for an examination:

• prolonged or regular darkening of vision that recurs for no apparent reason
• a pronounced state where dizziness and darkening of vision occur together
• fainting or near-fainting
• a noticeable deterioration in vision or loss of sharpness
• pain in the eyes or head that gets worse over time

You should also pay attention if you have persistent cloudy vision that does not go away even after rest and may gradually get worse.

What to do if your vision goes dark

If your vision suddenly goes dark, it is important not to ignore it and to respond correctly:

• stop and take a stable position
• if possible, sit or lie down to reduce the risk of falling
• get some fresh air
• drink some water, especially if there are signs of dehydration

If the symptoms recur, you need to be examined to find out exactly what is causing your cloudy vision and to choose the right treatment based on the cause.

At the British Ophthalmological Center, we carry out a comprehensive eye examination and help pinpoint the source of such symptoms. This makes it possible not only to relieve unpleasant symptoms but also to prevent more serious diseases from developing in good time.

To know exactly what is happening with your eyes, have a complete eye examination — the doctor will check all the structures of the eye and explain the results.