By Eyecare NG

Introduction   |  Causes   |   What to do 


Your vision is said to be blurred if objects appear hazy or cloudy while looking at them.

Blurred vision is a common eye symptom that can occur under various circumstances. It could occur while looking at a distant or near object, in one or both eyes, under bright or dim lighting and could be transient or continuous.

The circumstance under which blurred vision occurs could be an indicator of the specific condition(s) causing it. Therefore, it is necessary to consult an eye care professional for a proper eye examination, diagnosis and treatment when you have blurred vision. This is particularly important if blurred vision appears suddenly, persists or worsens rapidly.

Causes of Blurred Vision

The common causes of blurred vision fall into the following categories:

  1. Refractive errors and presbyopia
  2. Other eye conditions and diseases
  3. Medical conditions with eye symptoms

Refractive Errors and Presbyopia

Refractive errors ( myopia, hyperopia and astigmatism) and presbyopia are the primary causes of blurred vision.

In these conditions, blurred vision occurs because light entering the eyes fail to focus sharply on the retina (the most sensitive part of your eyes).

In myopia (nearsightedness), the eyeball is too long or the cornea is too curved. This causes light entering into it to focus in front of the retina resulting in blurred vision at far.

In hyperopia (far-sightedness), the eyeball is too short or the cornea is too flat. This causes light rays entering into it to focus behind the retina resulting in blurred vision at near.

In astigmatism, the curvature of the cornea is irregular. Light entering the eye under this condition fails to come to a single focus on the retina resulting in blurred vision at near and at far with images looking distorted.

In presbyopia, age-related changes in the lens gradually limit its ability to focus light on the retina during near work. Hence, a person who has presbyopia will experience blurred vision while performing near tasks such as reading small prints or threading a needle.

Other Eye Conditions and Diseases

Eye diseases and other eye health conditions that may cause blurred vision include:

Amblyopia: In Amblyopia, vision is decreased and blurred in one or both eyes because of poor stimulation of the eyes in the early years of life.

Cataract: Blurred vision in cataract is caused by the clouding of the lens.

Glaucoma: Glaucoma is a group of eye conditions that gradually damage the optic nerve resulting in progressive loss of vision. Blurred vision is usually observed when there is a build of fluids in the eye or as vision loss progresses.

Medical Conditions with Eye Symptoms

Blurred vision can also be a symptom of other health problems which could be life-threatening in some cases.  Examples of these health conditions are:

Diabetes: Diabetes is a group of diseases that result in high levels of sugar circulating in the blood. It causes blurred vision when the blood sugar level is so high that the lens swells up and its focusing ability gets affected.

Hypertension: This is a prolonged increase in blood pressure beyond the normal levels. It can damage the blood vessels in the retina and cause fluid to build up in the eye. It can cause blurred vision and also lead to permanent vision loss if the condition is not brought under control.

Multiple Sclerosis: This is an auto-immune disease that damages the central nervous system and interfers with communication between the brain and other parts of the body. It causes blurring of vision if the optic nerves are affected.

Pre-eclampsia: A condition in pregnant women characterized by high blood pressure, water retention, and protein in the urine. Severe cases can cause blurred vision due to a build-up of fluids in the eyes.

What to do when you have blurred vision

If you experience mild and transient blurring of vision particularly after prolonged use of your digital devices like the computer, try resting your eyes.

If blurred vision is mild and persistent, you should plan to see your doctor as soon as possible for proper diagnosis and treatment.

If blurred vision appears suddenly or worsens rapidly, consult your eye doctor immediately as a sudden change in vision could be a symptom of a serious eye disease or other health condition.