Learn about the causes, symptoms and different types of cataracts.
May 24, 2016
What is a cataract?
A cataract is a cloudy area in the lens of the eye that affects vision, and occurs as a natural part of aging. A healthy lens is clear, but as a cataract develops, the lens of the eye gradually becomes hard and cloudy, allowing less light to pass through and making it more difficult to see.1
There are three common types of age-related cataracts that can affect vision:
Nuclear cataract: the most common type of cataract and caused by the nucleus of the lens hardening or becoming opaque (cloudy)
Posterior subcapsular cataract: a dense area that forms just in front of the posterior lens capsule (the back of the lens capsule)
Cortical cataract: develops in the lens cortex, the outside edge of the lens and has a distinctive spoked appearance
What causes age-related cataracts?
Most cataracts develop from advanced aging.1 As the body ages, the lens of the eye, which consists of water and protein, can become cloudy due to protein clumping together, scattering the light landing on the retina and causing visual impairment. When the cataract blocks light, vision is disrupted.3 A cataract can develop in one or both eyes, but is independent and cannot spread from one eye to another. This condition also is more likely to occur due to the following:1,2
Excessively drink alcohol
High body mass index (BMI)
Ultraviolet (UV) light exposure
After an unrelated eye surgery
What are the symptoms?
Age-related cataracts can develop slowly over many years; some people may not be aware they have them at first.3 In the early stages, a cataract may not cause any vision problems and initially, the cloudiness may affect only a small part of the lens. Over time, the cataract may grow larger and cloud more of the lens, making it more difficult to see objects clearly.2
Early symptoms include blurriness and needing more light to read, even while wearing glasses. Other common symptoms include glare, halos, double vision, difficulty with distance or near vision, and colors looking faded.3 If left untreated, cataracts can lead to blindness.2 As they develop and worsen, cataracts may also interfere with the ability to perform basic activities, such as driving and reading.3
How are cataracts diagnosed?
An eye care professional can diagnose the presence of a cataract during a comprehensive eye exam through a visual acuity test and a dilated eye exam.2
How are cataracts treated?
Cataracts are treated by removing the eye’s cloudy natural lens and replacing it with an artificial intraocular lens (IOL). An IOL is a man-made lens and is placed inside the eye during surgery. There are three types of IOLs:
Monofocal IOLs have one point of focus, either distance or close up.
Multifocal IOLs provide two or more points of focus and are designed to reduce the dependence on reading glasses as a result of presbyopia.
Toric IOLs are designed to correct astigmatism, potentially reducing the need for glasses.
Cataract surgery is one of the most cost-effective surgeries, and patients can return to their normal routines within 24 hours.4