Cataract

A cataract is a condition where the clear lens inside the eye becomes cloudy, leading to blurry or dim vision. It affects the eye's lens, which normally helps focus light onto the retina for clear sight. As the lens becomes more opaque, it blocks or scatters light, causing problems with seeing clearly. People with cataracts often notice difficulty seeing at night, sensitivity to bright lights, or colors appearing faded. This condition mainly affects older adults but can also result from injury, certain medications, or other health problems. Cataracts are a common cause of vision loss worldwide and can significantly impact daily activities like reading or driving.

Cataract is defined as the opacification of the crystalline lens of the eye, resulting in decreased visual acuity. The core pathology involves protein aggregation and lens fiber disorganization, often due to oxidative damage and age-related changes in lens proteins such as crystallins. Common causes include aging, diabetes mellitus, prolonged UV light exposure, trauma, and certain medications like corticosteroids. The clinical significance lies in its progressive impairment of vision, which can lead to functional blindness if untreated. Cataracts are classified by their location within the lens (nuclear, cortical, posterior subcapsular) and can be congenital or acquired. Diagnosis and management are critical to prevent irreversible vision loss.