Cataracts

Cataracts are a gradual clouding of the eye\u0027s lens, most often with age, causing blurred vision, glare sensitivity, faded colours and difficulty with night driving. They develop slowly over years and are the leading cause of reversible blindness worldwide. No supplement or eye drop has been shown in good trials to reverse or reliably slow cataracts; surgery to replace the lens is highly effective when vision affects daily life. Antioxidant supplements are sometimes marketed for eye health but evidence for prevention is weak.

• •Gradually blurring or clouded vision
• •Increasing glare and halos around lights at night
• •Colours appearing faded or yellowed
• •Needing brighter light to read
• •Frequent changes in glasses prescription
• •Double vision in one eye
• •Improved near vision temporarily in early nuclear cataract

• •Age — the dominant factor
• •Cumulative ultraviolet B exposure
• •Smoking
• •Diabetes and poor glycaemic control
• •Long-term corticosteroid use
• •Eye injury or previous eye surgery
• •Congenital and genetic forms

Lens crystallin proteins are laid down before birth and never replaced, so damage accumulates over a lifetime. Oxidative stress, glycation from elevated glucose and ultraviolet exposure cause these proteins to cross-link and aggregate, scattering light instead of transmitting it. Because the proteins cannot be renewed, the change is irreversible — which is why no supplement can clear an established cataract.