Cataract - Types, Causes, and Risk Factors
                     Cataract: Types, Causes, and Risk Factors
What Is a Cataract?
A cataract is a dense, cloudy area that 
forms in the lens of the eye. A cataract 
begins when proteins in the eye form 
clumps that prevent the lens from sending 
clear images to the retina. 
The retina works by converting the light 
that comes through the lens into signals. It 
sends the signals to the optic nerve, which 
carries them to the brain.
Source: www.healthline.com
Symptoms of Cataracts
• blurry vision
• trouble seeing at night
• seeing colors as faded
• increased sensitivity to glare
• halos surrounding lights
• double vision in the affected eye
• a need for frequent changes in 
prescription glasses
Source: www.healthline.com
What Causes 
Cataracts?
• an overproduction of oxidants, which are 
oxygen molecules that have been 
chemically altered due to normal daily 
life
• smoking
• ultraviolet radiation
• the long-term use of steroids and other 
medications
• certain diseases, such as diabetes
• trauma
Source: www.healthline.com
Types of Cataracts
There are many types of cataracts.
Nuclear cataracts
Also called a nuclear sclerotic cataract, this 
is the kind doctors see most. Anyone who 
lives long enough usually ends up with one.
Source: www.healthline.com
Cortical cataracts
These take shape on the outside edge of 
your lens, called the cortex. They start as 
white wedges, like triangles that point 
toward the center of your eye. As they 
grow, they scatter light.
Source: www.webmd.com
Posterior subcapsular 
cataracts
These form just inside the back of your lens 
capsule, the part of your eye that 
surrounds the lens and holds it in place. 
They're directly in the path of light as it 
passes through the lens.
Source: www.webmd.com
Anterior subcapsular 
cataracts
This type forms just inside the front of your 
lens capsule. An injury or swelling in your 
eye can lead to one. So can a type of 
eczema called atopic dermatitis.
Source: www.webmd.com
Risk Factors of 
Cataracts
• older age
• heavy alcohol use
• smoking
• obesity
• high blood pressure
• previous eye injuries
• a family history of cataracts
• too much sun exposure
• diabetes
• exposure to radiation from X-rays and 
cancer treatments
Source: www.healthline.com
Diagnosing Cataracts
Your doctor will perform a comprehensive 
eye exam to check for cataracts and to 
assess your vision. This will include an eye 
chart test to check your vision at different 
distances and tonometry to measure your 
eye pressure.
Source: www.healthline.com