Cataracts

Overview

A cataract is clouding of the natural lens of the eye, which lies behind the iris and pupil. As the lens clouds over, light cannot pass through clearly, causing progressive blurring of vision. Cataracts are the leading cause of reversible blindness worldwide.

How common is it?

By age 65, about half of all people have some degree of cataract. By age 75, nearly all people have lens changes significant enough to affect vision.

Causes and risk factors

Most cataracts result from age-related changes to lens proteins that cause them to clump and cloud. The process accelerates with various exposures and conditions.

Common risk factors

• Ageing
• Prolonged UV light exposure without sunglasses
• Diabetes
• Smoking
• Long-term use of corticosteroids
• Previous eye injury or eye surgery
• Certain genetic conditions

Symptoms

• Gradual blurring or clouding of vision
• Increased sensitivity to glare (especially when driving at night)
• Seeing halos around lights
• Colours appear faded or yellowed
• Difficulty reading small print even with glasses
• Frequent changes in prescription glasses strength
• Double vision in one eye

When to see a doctor

See an optometrist for an eye test if your vision is blurring or if glare is affecting driving or daily activities. An eye test every 2 years is recommended for adults.

Diagnosis

Optometrists detect cataracts during routine slit-lamp examination of the eye. Visual acuity testing quantifies vision loss. Ophthalmologists confirm the diagnosis and assess whether surgery is appropriate.

Treatments

Self-care and lifestyle

• Wear UV-blocking sunglasses outdoors to slow cataract development
• Quit smoking
• Manage diabetes well to reduce the pace of cataract formation
• Ensure bright directed lighting for reading and close work

Prevention

Wearing sunglasses, not smoking, controlling diabetes, and protecting eyes from injury all slow cataract formation. Cataracts cannot be fully prevented.