Cataract: Facts, Symptoms & Treatment

A cataract is a clouding of the lens in the eye that affects human vision. Also most cataracts are related to aging. Cataracts are very common in older people, mostly from 70 to 90 years and above.

A survey carried out by Nigerian National Blindness and visual impairment showed that 42 out of every 1,000 adults aged 40 and above are blind and overall, two out of every three Nigerians are blinded by avoidable causes like cataract.

Also, National Institutes of Health (NIH) United States of America, stated that more than half of all Americans either have a cataract or have had cataract surgery.

A cataract can occur in one eye or both eyes. It cannot spread from one eye to the other.




  • Cataract is a clouding of the lens of the eye, and it develops when proteins in the lens clump together.
  • Cataracts can be caused by factors such as ultraviolet radiation (sun exposure), obesity, smoking, eye injury, high myopia and steroid medications.
  • The three types of cataracts are sub-scapular, nuclear and cortical.
  • Common symptoms of cataracts include blurred vision, double vision, increased glare, appearance of halos around lit objects, and faded appearance of colors.
  • Cataract-related vision loss is reversible with cataract surgery.
  • Cataract surgery is one of the safest and most common surgeries in the world.
  • During cataract surgery, the deteriorated lens is removed and replaced with a customized, artificial prescription lens called an intraocular lens (IOL).
  • According to the latest assessment by World health organization (W.H.O), cataract is responsible for 51% of world blindness, which represents about 20 million people (2010).
  • According to World health organization (W.H.O), one in six persons at the age of 70 and above have cataract in the world.
  • Cataract without cure can lead to complete blindness. 





Most cataracts develop when aging or injury changes the tissue that makes up your eye’s lens.

Some are caused by inherited genetic disorders that cause other health problems that can increase your risk of having cataracts.

Cataracts can also be caused by other eye conditions, past eye surgery or medical conditions such as diabetes. Long-term use of steroid medications, too, can cause cataracts to develop.

The lens, where cataracts form, is positioned behind the colored part of your eye (iris). The lens focuses light that passes into your eye, producing clear, sharp images on the retina — the light-sensitive membrane in the eye that functions like the film in a camera.




How it forms

Most cataracts develop when aging or injury changes the tissue that makes up your eye’s lens.

Some are caused by inherited genetic disorders that cause other health problems which can increase your risk of having cataracts.

As you age, the lenses in your eyes become less flexible, less transparent and thicker. Age-related and other medical conditions cause tissues within the lens to break down and clump together, clouding small areas within the lens.

As the cataract continues to develop, the clouding becomes denser and involves a bigger part of the lens. A cataract scatters and blocks the light as it passes through the lens, preventing a sharply defined image from reaching your retina. As a result, your vision becomes blurred.

Researchers suspect that there are several causes of cataract, such as smoking and diabetes. Or, it may be that the protein in the lens just changes due to the wear and tear it takes over the years.





Signs and symptoms of cataracts include:

  • Clouded, blurred or dim vision.
  • Increasing difficulty with vision at night.
  • Sensitivity to light and glare.
  • Need for brighter light for reading and other activities.
  • Seeing “halos” around lights.
  • Frequent changes in eyeglass or contact Lens.
  • Fading or yellowing of colors.
  • Double vision in a single eye.
  • Poor night vision.





To determine whether you have a cataract, an ophthalmologist or optometrist will review your medical history and symptoms, and perform an eye examination. The doctor may conduct several test which includes;


Visual Acuity Test

A visual acuity test uses an eye chart to measure how well you can read a series of letters. Your eyes are tested one at a time, while the other eye is covered.

Using a chart or a viewing device with progressively smaller letters, your eye doctor determines if you have 20/20 vision or if your vision shows signs of impairment.


Slit-Lamp Examination

A slit lamp allows your eye doctor to see the structures at the front of your eye under magnification.

The microscope is called a slit lamp because it uses an intense line of light, a slit, to illuminate your cornea, iris, lens, and the space between your iris and cornea. The slit allows your doctor to view these structures in small sections, which makes it easier to detect any tiny abnormalities.


Retinal Exam

To prepare for a retinal exam, your eye doctor puts drops in your eyes to open your pupils wide (dilate). This makes it easier to examine the back of your eyes (retina).

Using a slit lamp or a special device called an ophthalmoscope, your eye doctor can examine your lens for signs of a cataract.





This is done when your prescription glasses can’t clear your vision, the only effective treatment for cataracts would be surgery. This involves the removal of your cloudy lens and replacing it with an artificial one (lens).

Note: A cataract needs to be removed only when vision loss interferes with your everyday activities, such as driving, reading, or watching TV.


When to consider cataract surgery?

surgery is right for you. Most eye doctors suggest considering cataract surgery when your cataracts begin to affect your quality of life or interfere with your ability to perform normal daily activities, such as reading or driving at night.

It’s up to you and your doctor to decide when cataract surgery is right for you. For most people, there is no rush to remove cataracts because they usually don’t harm the eye. But cataracts can worsen faster in people with diabetes.

Delaying the procedure generally won’t affect how well your vision recovers if you later decide to have cataract surgery. Take time to consider the benefits and risks of cataract surgery with your doctor.

If you choose not to undergo cataract surgery now, your eye doctor may recommend periodic follow-up exams to see if your cataracts are progressing. How often you’ll see your eye doctor depends on your situation.







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