Causes of Blurred Vision: Why Does Vision Become Hazy and When Should You See a Doctor?

Causes of Blurred Vision: Why Does Vision Become Unclear?

Blurred or hazy vision is a common condition that many individuals experience. It may occur gradually or suddenly, affecting one eye or both. While the sensation of blurred vision seems the same, the medical causes vary greatly, and determining the exact reason requires a comprehensive eye examination.

In this article, we explain the most common causes of blurred vision, how each cause affects the eye, and when you should seek professional evaluation.

Causes of Blurred Vision

1) Refractive Errors

These are the most common causes of blurred vision and include:

a) Myopia (Nearsightedness)

Near objects appear clear, while distant objects appear blurry.
This occurs when the eyeball is longer than normal or when the cornea is too curved, causing light to focus in front of the retina.

b) Hyperopia (Farsightedness)

In this case, near objects appear blurry, while distant ones may seem clearer.
It occurs due to a shorter than normal eyeball or a flatter corneal curvature.

c) Astigmatism

The cornea has an irregular shape, causing light to focus at multiple points instead of one, leading to distorted vision at all distances.

d) Presbyopia

Common after the age of 40, caused by loss of flexibility in the natural lens, leading to difficulty focusing on near tasks such as reading.

Note: Refractive errors are not diseases but require accurate vision testing and correction.

2) Dry Eye Syndrome and Tear Film Instability

Tears help maintain a smooth and clear surface of the cornea.
When tear production decreases or the tear quality changes, the corneal surface becomes unstable, resulting in:

• Fluctuating blurriness throughout the day
• Difficulty seeing clearly when using digital screens
• Burning or stinging sensations

Those at higher risk include:

• Contact lens wearers
• Individuals who work long hours on screens
• People exposed to dry or air-conditioned environments

If blurred vision is accompanied by burning or a gritty sensation, dry eye may be the cause.

Read also: Dry Eyes: Causes, Symptoms, and Treatment

3) Corneal Inflammation or Surface Abrasions

The cornea is the clear window of the eye.
Any inflammation, scratch, or allergic reaction can distort how light enters the eye, causing noticeable blurriness.

Possible causes include:

• Improper contact lens hygiene
• Bacterial or viral infections
• Seasonal allergies

4) Keratoconus

A progressive condition where the cornea thins and bulges into a cone shape, resulting in:

• Blurred vision
• Visual distortion
• Poor night vision

It often appears in teenagers and young adults and may progress over time.

5) Cataracts

The natural lens should be crystal clear.
When it becomes cloudy due to aging or other factors, you may experience:

• Gradual vision cloudiness
• Faded color perception
• Halos around lights
• Difficulty seeing at night

Cataracts are one of the most common causes of blurred vision after age 50.

6) Diabetic Retinopathy

The retina converts light into nerve signals.
Long-term high blood sugar levels can damage the tiny retinal blood vessels, leading to:

• Leakage or swelling
• Progressive vision loss

It often develops without noticeable symptoms early on.

7) Elevated Eye Pressure and Glaucoma

High intraocular pressure can damage the optic nerve, leading to:

• Blurred vision
• Eye pain
• Headache
• Gradual narrowing of the visual field

Early diagnosis is essential to prevent permanent vision loss.

8) Optic Neuritis

The optic nerve carries visual signals to the brain.
Inflammation can disrupt this transmission, causing:

• Blurred or foggy vision
• Pain when moving the eyes

It may be associated with:

• Autoimmune diseases
• Multiple sclerosis
• Viral infections

9) Ocular Migraine (Visual Migraine)

Before or during a migraine, some individuals may experience:

• Blurred vision
• Light flashes
• Zigzag patterns

These symptoms typically last 20–60 minutes.

10) Sudden Changes in Blood Sugar

Sudden increases or decreases in blood glucose can temporarily change the shape of the lens, leading to blurred vision.

Common among individuals with uncontrolled diabetes.

11) High Blood Pressure

High blood pressure can affect:

• The retinal blood vessels
• The optic nerve

Leading to sudden blurred or dim vision requiring urgent evaluation.

12) Medication

Certain drugs can alter tear production or nerve function, such as:

• Antidepressants
• Antihistamines
• Epilepsy medications

13) Eye Injuries

Trauma may affect:

• Cornea
• Lens
• Retina

Resulting in temporary or persistent blurred vision depending on the injury.

14) Retinal Detachment (Emergency)

If blurred vision is accompanied by:

• Sudden flashes of light
• Floating black spots
• A shadow or curtain-like effect

When Should You See an Eye Doctor Immediately?

Seek urgent evaluation if blurred vision is:

• Sudden or rapidly worsening
• Accompanied by eye pain or severe headache
• Following eye or head trauma
• Associated with numbness or weakness in the body

Schedule Your Blurred Vision Examination at Batal Specialized Eye Center

Since the cause determines the treatment, the first step is accurate diagnosis.

At Batal Specialized Eye Center in Jeddah, we perform:

• Comprehensive vision testing
• Corneal imaging
• Retinal and optic nerve scans
• Eye pressure measurements

To identify the exact cause and design a personalized treatment plan.

Your vision matters — don’t ignore the signs. Contact us today to book your eye examination.