It can be decided that treatment is required when cataracts begin to disrupt the quality of vision, causing problems in the individual's daily activities (safe driving, reading, watching TV).
Based on your symptoms, together with your ophthalmologist you will mutually decide on when to have the surgery.
It is no longer true that cataracts need to be "ripe" to be surgically removed. With new techniques (
phacoemulsification, laser) that perception is outdated.
In fact, the removal of an overripe, hard cataract, makes surgery much more difficult.