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CATARACTS : About,Causes,Factors,Types and Symptoms


What Are Cataracts?

CATARACTS is the major cause of blindness worldwide. It is clouding of the lens of the eye that creates hindrance in reaching of light to the retina. This leads to blurred vision and other vision issues.

The lens is situated between iris and pupil. It’s the clear part of the eye that enables focus the light onto the retina. The retina is the light-sensitive tissue behind the eye which converts light signals to electrical impulses which the brain interprets into images.

What Causes Cataracts?

The lens generally consists of water and protein, which is organized precisely that keeps the lens clear and enables light to go through to the retina.

But sometimes the proteins in a small zone of the lens coagulate leading to clouding of the lens.

Over time, the cataract may enlarge as more proteins clump together.

Age is the most important factor related to cataract. According to National Eye Institute, the risk of cataract increases with every decade after 40 years.

Surgery for other eye issues, (for example, glaucoma), eye damage, or exposure to various sorts of radiation can also be the cause of cataract development.

A few people have a tiny cataract at birth or develop in early childhood.


Different variables may increase the risk of cataract development which includes:

  • Smoking
  • Long-term utilization of corticosteroids
  • diabetes
  • Taking antipsychotic drugs in the phenothiazine classification, for example, Thorazine (chlorpromazine)
  • Eye inflammation
  • Excessive exposure to UV radiations
  • Positive family history of cataract
  • Alcoholism
  • Nutritional insufficiencies, for example, low intake of antioxidants

Types of Cataracts:

Classification of cataract is based on the location of cataract in the lens:

Nuclear sclerotic cataracts:

These are the most widely recognized type of cataract. These develop close to the center of the lens.

As they build up, the core of the lens solidifies and darkens after some time, turning yellow and eventually becomes brown.

When the core solidifies, it can also lead to nearsightedness.

Cortical cataracts:

These influence the layer of the lens that encompasses the nucleus. They often start at the outer part of the lens as whitish wedge-like opacities, gradually growing inward as they advance.

This kind of cataract frequently causes issues with glare, for example, from headlights around evening time.

Posterior subcapsular cataracts:

These develop in the posterior external layer of the lens, specifically in the way of light heading towards the retina.

This sort of cataract can influence your vision in different ways, for example, causing halos around the light.

Cataract Prevalence:

Cataracts are the main cause of visual impairment worldwide. According to WHO cataracts are responsible for approximately 51% of cases of blindness around the world (around 20 million individuals).

In the United States, near 20 million individuals ages 40 and above — around 16 percent of the population suffer from cataracts, as per the Centers for Disease Control and Prevention (CDC). According to CDC, 61% of cataract patients in the US are females.

Cataracts are more typical in white Americans as compared to other racial and ethnic communities.

The incidence rate of cataract among white Americans is around 50 percent by age 75 and 70 percent by age 80.

In contrast, just 53 percent of black Americans and 61 percent of Hispanic Americans have a cataract by age 80.


Initially, when the cataract is small, the patient is asymptomatic. It can cause:

  • Blurred or dim vision
  • Distortion of color vision
  • Night blindness
  • Double vision
  • Inability to perceive colors
  • Improved close vision
  • Glare — in which headlights, lights, and other light sources show up too bright, or with coronas show up around them


The only possible treatment for cataract is eye surgery to remove and supplant the lens.

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