Everybody has cataract. It isn't a thing, it's a growing cloudiness in your eyes. It happens gradually as you age, but gets bad fast for some people. Effectively it's like slightly dirty lenses in your glasses. Reduces contrast but doesn't always make vision poor.
Older people have worse eyesight and slower reactions, but better driving experience and they are more risk averse.
Insurance companies take risks into account when assessing premiums. Even though older people are more frail and more likely to be injured in an accident, they pay lower premiums than average. Far, far lower premiums than teenagers.
Go figure.