Well, generally speaking, it can lead to the blindness. As we know that A cataract is a clouding of the normally clear lens of the eye, which can eventually block the central line of sight and impairs vision. Cataract surgery is an operation to remove the clouded lens. Especially if the operation has complications, it creases the risk of a retinal detachment. So if you have the retinal detachment, it can lead to blindness. But on the other hand, it is safe to take the surgery, so you should not worry about it. And after the surgery, there are some risks to have infection on your eyes, so just be careful about it. For example, you should not watch TV or computer in the first week, and also should be careful when you have shower.
No, it will not cause the blindness if your cataract surgery fails. Cataract is a common ophthalmopathy that may lead to the blindness. People eyes have an organization called the lens. Under normal circumstances, it is transparent. When the light goes through it and some refractive interstitial reach the retina, it can clearly see the objects in the outside world. Once the lens for some reason occurred cloudy, they will affect retinal imaging which will make the person not see things clearly. That is to say, lens opacity causes vision loss in cataract. If you have got the cataract, you'd better get the timely treatment. At the same time, you should pay attention to some tips to avoid long-term excessive use of eyes. Or else, the eyes may get blurry at vision again after the cataract surgery.