Cataracts

Understanding Cataracts

What Are Cataracts? Cataracts are cloudy or opaque areas in the normally clear lens of the eye, causing vision problems. The lens, located behind the iris, focuses light on the retina, which sends images to the brain. A cataract scatters light, preventing the lens from focusing properly. Cataracts typically develop in people over 55, but can also occur in infants, young children, or as a result of trauma or medication. Often, cataracts develop in both eyes, though one may be worse than the other.

Explore our interactive eye graphic to see how cataracts work.

Types of Cataracts

The lens consists of layers like an onion: the outer capsule, the cortex, and the inner nucleus. Cataracts are named for their location in these layers:

• Nuclear Cataract: Located in the center of the lens, it darkens with age.

• Cortical Cataract: Affects the layer surrounding the nucleus, appearing as wedges or spokes.

• Posterior Capsular Cataract: Found in the back outer layer of the lens and develops rapidly.

Causes and Risk Factors

Most cataracts result from age-related changes in the lens. Other contributing factors include:

• Diabetes Mellitus: Higher risk for cataracts.

• Medications: Such as corticosteroids and phenothiazine-related drugs.

• Ultraviolet Radiation: Increased risk with unprotected UV exposure.

• Smoking and Alcohol: Both are linked to increased cataract formation.

• Nutritional Deficiency: Low levels of antioxidants like vitamins C and E, and carotenoids.

• Family History: Higher risk if a close relative has had cataracts.

• Other Factors: Eye injuries, surgeries, or radiation treatments.

Symptoms

Cataracts develop slowly, with symptoms including:

• Blurred or hazy vision

• Reduced color intensity

• Increased sensitivity to glare

• Difficulty seeing at night

• Frequent changes in eyeglass prescription

Diagnosis

Cataracts are diagnosed through comprehensive eye exams, which may include:

• Visual acuity measurement

• Refraction tests for prescription changes

• Examination of the lens under high magnification

• Pupil dilation for retina evaluation

• Eye pressure measurement

• Tests for color vision and glare sensitivity

Treatment

Treatment depends on the level of visual impairment:

• Early Stages: New eyeglass prescriptions and anti-glare coatings can help. Brighter lighting can also be beneficial.

• Surgery: When cataracts significantly affect daily activities, surgery is needed. This involves replacing the clouded lens with an artificial one. Two common surgical approaches are:

  • Phacoemulsification: A small incision and ultrasound waves soften and remove the lens.

  • Extracapsular Surgery: A larger incision removes the lens in one piece, replaced by an intraocular lens (IOL).

Cataract surgery is safe and effective, with 90% of patients reporting improved vision.

Prevention

While no method guarantees cataract prevention, strategies include:

• Wearing UV-blocking lenses

• Reducing or quitting smoking

• Increasing antioxidant intake through diet and supplements

• Consuming eye-friendly nutrients like lutein, zeaxanthin, vitamins C and E, and zinc