Blurred vision? It might be time to think about glasses

By Cristiano Antonino Last updated Jun 20, 2023

If you have blurred vision, the cause could be failing eyesight and you may need new glasses. The reasons, however, could also be others! In fact, if the blurred vision is persistent, it may also be a sign of other health problems: let’s see what they are and when it is a good idea to contact your doctor and have a more thorough examination

Blurred vision refers to a reduction in the ability to clearly distinguish objects around us

Sudden changes in visual capacity are not normal, so if they occur, the best thing to do is to consult your doctor immediately.

Visual clouding is very often due to causes within the eye, for instance related to inflammatory states of the eye structures.

Conjunctivitis or keratitis can, for example, change the transparency of the cornea or cause hyperlacrimation, thus causing blurred vision.

With advancing age, the presence of cataracts, i.e. opacification of the crystalline lens, or changes to the vitreous body, the gel that fills the eyeball, can cause blurred vision with more or less rapid onset.

However, there are also many causes external to the eyes that, although more or less frequent, can cause sudden blurred vision.

Blurred vision and systemic blood pressure

If your eyesight only blurs at certain times, it is possible that it is due to a sudden drop in pressure, which tends to resolve spontaneously within a few seconds.

In this case, the clouding may also be accompanied by a sense of fainting, e.g. when standing up abruptly or after particularly intense physical activity.

The cause is to be found in a momentary reduction in blood supply.

Blurred vision does not exclusively result from a state of systemic hypotension, in fact it can also be linked to a hypertensive peak.

In particular, in pregnancy there is a condition known as pre-eclampsia, a dangerous condition characterised by very high blood pressure and protein in the urine.

Pre-eclampsia arises in women who have never had high blood pressure before gestation and generally occurs late in pregnancy, after 20 weeks.

The effects on the woman and the baby can be very serious, which is why it is essential to measure your blood pressure daily when you are pregnant.

This special attention is necessary because pre-eclampsia may not cause any symptoms, but blurred vision and other changes in vision – such as seeing flashing lights or spots – could be indications of a sudden and significant rise in blood pressure.

In this case, it is necessary to contact the gynaecologist following the pregnancy immediately, particularly if we notice the association of these symptoms:

Anxiety, shortness of breath, rapid heartbeat or confusion.
Nausea or vomiting that starts suddenly after the first trimester.
Pain in the belly, shoulder or lower back.
Sudden weight gain.
Swelling, especially of the face, eye area or hands.
Major headache resistant to medication.

Blurred vision due to diabetes

People with diabetes are more likely to develop eye diseases, such as diabetic retinopathy: this is because over time, high blood sugar levels can damage the tiny blood vessels in the retina, the part of the eye that perceives light.

This can lead to swelling in a part of the retina called the macula, and the formation of a cluster of new blood vessels in the eye and bleeding inside the eyeball.

Along with blurred vision, diabetic eye disease can also cause

Floating’ dots or dark spots in your field of vision.
Permanent loss of vision in the case of severe retinal damage.

Early treatment is the best way to prevent permanent damage.

So to protect your eyes from diabetes, it is advisable not only to keep the condition under control, but also to have a check-up eye examination at least once a year.

When migraine causes blurred vision

Migraine is mistakenly thought to be nothing more than a headache; in reality, it is a more complex condition that can have many symptoms.

In fact, there are a number of other symptoms that accompany the pain, including blurred vision and increased sensitivity to light.

It is possible that migraine begins with these very symptoms, which only end when the crisis ends.

There are also other dramatic changes in vision during migraine that are called auras.

They can include:

Partial or complete loss of vision for a short period (usually 30 minutes or less).
Seeing flashes of light.
Seeing wavy lines or spots.

In most cases you have to learn to live with the symptoms and manage them as best you can.

In order to manage the situation as best as possible, it will be necessary to collaborate with the general practitioner and neurologist for appropriate pain-relieving drug therapy if the frequency of attacks is high.

Blurred vision and the central nervous system

Blurred vision may be one of the symptoms associated with diseases of the central nervous system.

In this case it is often not the only symptom present, nor the most recognisable, as it is often accompanied by other, more peculiar symptoms.

In the dramatic case of a stroke, there may be a sudden and painless change in vision: blurred or double vision may occur.

In this case, the best thing to do is to go to the emergency room immediately, particularly if the blurred vision is associated with other symptoms, such as:

Dizziness
Feeling of falling face
Loss of balance
Slurred speech or other problems speaking clearly
Weakness or numbness in one arm

Blurred vision may be present in tumour diseases of the central nervous system, again accompanied by multiple other symptoms.

In fact, an expansive mass or lesion anywhere on the head could create pressure inside the skull, damaging internal structures including those responsible for vision.

In addition to blurred vision, there are other neurological signs that, if present, necessitate rapid clinical and instrumental investigation:

Drowsiness
Persistent headache
Nausea
Personality changes
Convulsions
Vomiting

In the presence of these symptoms, a comprehensive medical examination by a specialist is mandatory. Imaging tests, such as CT and MRI, can also be used to carefully study the intracranial structures.

Blurred vision is often one of the first symptoms of multiple sclerosis, an autoimmune demyelinating disease.

In this condition, the immune system mistakenly attacks the sheaths lining the nerve fibres and thus also the optic nerve, which is responsible for carrying visual information from the eyes to the brain.

This causes inflammation of the optic nerve and thus optic neuritis, which can lead to blurred vision, loss of colour vision and pain when moving the eyes.

Usually this inflammation of the optic nerve affects only one eye, but may in rare cases affect both.

In addition to blurred vision, other symptoms of multiple sclerosis are:

Problems with balance
Bladder and bowel problems
Dizziness
Tiredness
Numbness
Stiffness
Weakness

Beware, optic neuritis is not exclusive to multiple sclerosis, so the advice is to investigate – together with your general practitioner and a specialist – what the causes are.

Finally, blurred vision may be present in degenerative nerve diseases, but often not as the first symptom.

Parkinson’s disease is a condition that affects general motility causing poor balance and coordination, rigidity and widespread tremors.

The eyes are also not excluded from these alterations, so there will be difficulty with eye movements and keeping close objects in focus.

The disease can also alter the colour sense by damaging retinal receptors.

The action of the eyelids may also be impaired, reducing the blinking frequency and exposing the ocular surface: this causes dryness and burning of the eye with associated blurred vision.

Could psoriasis be the cause?

Perhaps not everyone knows that systemic autoimmune diseases can generate inflammation in various body regions including the eyes.

One of the most common, psoriasis particularly affects the skin and is generally characterised by these symptoms:

Itchy or irritated patches of skin
Joint pain and inflammation
Thick, red, scaly spots on the skin

If, apparently, the symptoms are far removed from anything to do with your eyesight, you should know that psoriasis can also affect your eyes.

Between 7 and 20 per cent of psoriasis patients may develop a condition called uveitis, an inflammatory condition that causes reddening and pain in the eyes, increased sensitivity to light, blurred vision, and decreased vision.

Treatments are aimed at extinguishing the inflammation locally, but it will be necessary to better investigate the causes to try to manage the condition from an overall perspective.

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