Cataracts develop when the lens of the eye becomes cloudy. 

For people who have cataracts, seeing through cloudy lenses is like looking through a frosty or fogged-up window. Clouded vision caused by cataracts can make it more difficult to read, drive a car at night, or see the expression on a friend’s face.

Most cataracts are related to aging and are very common in older people.

Early detection and treatment can prevent further vision loss and improve overall quality of life.

Symptoms of cataract 

• Clouded, blurred, or dim vision.
• Trouble seeing 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 prescription.
• Fading or yellowing of colors.
• Double vision in one eye.

Causes of cataract 

Aging: Most cataracts develop when aging or injury changes the tissue that makes up the eye’s lens. Proteins and fibers in the lens begin to break down. This causes vision to become hazy or cloudy.

Genetics: Some disorders passed down from parents that cause other health problems can increase your risk of cataracts.

Certain medical conditions: Cataracts also can be caused by other eye conditions, past eye surgery, or medical conditions such as diabetes.

Certain medicines: Long-term use of steroid medicines also may cause cataracts to develop.

Types of cataracts 

Nuclear cataract: This type of cataract affects the center of the lens.

Nuclear cataracts usually are associated with aging.

A nuclear cataract may at first cause objects far away to be blurry but objects up close to look clear. A nuclear cataract may even improve your reading vision for a short time. But with time, the lens slowly turns more yellow or brown and makes your vision worse. It may become difficult to tell colors apart.

Cortical cataracts: These are characterized by white, wedge-like opacities that start in the periphery of the lens and work their way to the center in a spoke-like fashion. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the central nucleus.

Posterior subcapsular cataracts: These develop at the back of the lens.

It often affects your reading vision. It also may reduce your vision in bright light and cause glare or halos around lights at night. These types of cataracts tend to grow faster than others.

Congenital cataracts: Some people are born with cataracts or develop them during childhood. These congenital cataracts may be genetic, or associated with an intrauterine infection or trauma.

These cataracts also may be due to certain conditions. These may include myotonic dystrophy, galactosemia, neurofibromatosis type 2, or rubella. Congenital cataracts don’t always affect vision. If they do, they’re usually removed soon after they’re found.

Secondary cataracts: These are cataracts that are formed due to other medical conditions, like diabetes, or exposure to toxic substances, certain drugs (such as corticosteroids or diuretics), ultraviolet light, or radiation.

Risk factors for cataracts

• Increasing age.
• Diabetes.
• Getting too much sunlight.
• Smoking.
• Obesity.
• Family history of cataracts.
• Previous eye injury or inflammation.
• Previous eye surgery.
• Prolonged use of corticosteroid medicines.
• Drinking excessive amounts of alcohol.

How to prevent cataracts 

• Regular eye exams.
• Do not smoke. 
• Manage other health problems.
• Choose a healthy diet that includes plenty of fruits and vegetables. 
• Reduce alcohol use.
• Wear sunglasses.

Diagnosing cataracts 

• Vision test. A vision test, also called a visual acuity test, uses an eye chart to measure how well you can read a series of letters. One eye is tested at a time, while the other eye is covered. A chart or a viewing device with letters that get smaller is used. With this, your eye doctor determines if you have 20/20 vision or if you have trouble seeing.

• Eye structure exam. An eye structure exam also called a slit lamp, allows your eye doctor to see the structures at the front of your eye up close. It’s called a slit lamp because it uses an intense line of light, a slit, to light up the structures in your eye. The slit allows your doctor to view these structures in small sections. This makes it easier to find anything that may be wrong.

• Retinal exam. A retinal exam looks at the back of your eyes, called the retina. To prepare for a retinal exam, your eye doctor puts drops in your eyes to open your pupils wide, called dilation. This makes it easier to see the retina. Using a slit lamp or a special device called an ophthalmoscope, your eye doctor can examine your lens for signs of a cataract.

• Fluid pressure test. This test, also called applanation tonometry, measures fluid pressure in your eye. There are multiple different devices available to do this.