"Cataract" is the name used to describe a condition where the lens of the eye becomes opacified, blocking some light from reaching the retina and interfering with vision. Cataracts are multi-faceted. The most common cause is age related, other known causes include: diabetes, trauma, certain medications and rare systemic diseases.
Typically, cataracts occur in adults ("adult onset"), but may occur as a congenital disorder. Fortunately congenital cataracts are rare, but these need to be diagnosed and managed urgently.
Early symptoms of cataracts include blurred or cloudy vision, frequent changes in eyeglass or contact lens prescriptions, night glare and hazy vision. These symptoms can also be caused by various other eye diseases and a careful eye examination will reveal the underlying cause
For an adult, a cataract should be removed only when it interferes with lifestyle and makes it difficult to continue normally enjoyable activities. Generally, there is no such thing as a cataract being "ripe" or "not ripe" for removal. What matters is whether or not the problem interferes with vision.