A cataract is a clouding of the eye’s natural lens, which focuses light onto the retina. The lens is composed of water and proteins arranged to keep it clear. When these proteins break down and clump together, the lens becomes opaque, similar to looking through a foggy window. This progressive clouding interferes with light passage, causing a gradual decrease in vision quality.
Prevalence and the Role of Age
Cataracts are considered a common and virtually inevitable part of the human aging process. Age is the most significant factor in their development and they are the leading cause of blindness globally. Changes in the lens can begin as early as a person’s 40s, though symptoms may not be noticeable for many years.
The prevalence of cataracts rises dramatically with age. Approximately one-third of Americans over the age of 70 have cataracts. By age 75, roughly half of all people have developed a cataract, and this figure increases to about two-thirds of individuals aged 80 and older.
Factors That Increase Risk
While age is the primary driver, certain health and lifestyle factors can accelerate cataract formation or cause them to develop younger. For instance, having diabetes increases the risk because prolonged high blood sugar levels can damage the lens. This damage often leads to earlier cataract development in individuals with poorly controlled blood sugar.
Lifestyle choices also promote the breakdown of lens proteins. Excessive, unprotected exposure to the sun’s ultraviolet (UV) radiation is a known risk factor, as UV rays induce oxidative stress. Other factors that contribute to risk include:
- Smoking tobacco.
- Heavy alcohol consumption.
- Genetic predisposition.
- A family history of cataracts.
- Long-term use of certain medications, such as corticosteroids.
Recognizing the Signs
The symptoms of a developing cataract are subtle initially but become more pronounced as the lens clouding progresses. Vision commonly appears cloudy, blurred, or dim, as if viewed through a hazy film. Colors may also seem faded or yellowed because the clouded lens filters the light.
Difficulty seeing clearly at night is a frequent complaint, often accompanied by increased glare or halos around light sources. Some people experience a temporary improvement in near vision, known as a myopic shift, or require frequent changes to their eyeglass prescription. An eye care professional can detect a cataract during a comprehensive eye examination using a slit lamp.
How Cataracts Are Managed
In the early stages, vision may be managed non-surgically by updating eyeglass prescriptions, using stronger bifocals, or ensuring better lighting. These measures compensate for reduced clarity but do not stop the cataract from progressing. When the cataract significantly interferes with daily life, surgery becomes the recommended course of action.
Modern cataract surgery, typically using a technique called phacoemulsification, is a common and successful procedure. The surgeon creates a tiny incision in the cornea and uses a probe that emits ultrasonic waves to break up the cloudy lens into small pieces. These fragments are then suctioned out of the eye.
Once the natural lens material is removed, a clear, artificial intraocular lens (IOL) is inserted into the capsule, restoring clear vision. This replacement lens is made of a medical-grade material that is immune to future cataract formation. The incision is often self-sealing and requires no stitches, contributing to a rapid recovery period.