What is cataract?

A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil. Cataracts are typically associated with aging, but they can also occur due to other factors such as injury, certain medications, and medical conditions like diabetes. The clouding of the lens leads to blurred vision, difficulty seeing in dim light, sensitivity to glare, and other visual disturbances.


Cataracts develop when proteins in the lens clump together, causing the lens to become less transparent and impairing the passage of light through the eye. This clouding can progress over time, gradually worsening vision. Cataracts are a common cause of vision loss among older adults and can significantly impact daily activities such as reading, driving, and recognizing faces.


What is the relationship between cataract and oxidative stress?

Oxidative stress has been implicated in the development and progression of cataracts. Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body’s ability to neutralize or detoxify them. ROS, such as free radicals, can damage various cellular components, including proteins, lipids, and DNA.


In the lens of the eye, oxidative damage can lead to the accumulation of oxidized proteins and other molecules, contributing to the formation of cataracts. The lens is particularly susceptible to oxidative damage because it contains high concentrations of proteins and lipids and has limited repair mechanisms.


Several factors can increase oxidative stress in the lens, including aging, exposure to ultraviolet (UV) radiation from sunlight, smoking, diabetes, and certain medications. These factors can lead to the production of ROS and impair the antioxidant defense systems that normally protect against oxidative damage.