This is one of the most common successful surgeries. How much improvement is achieved is dependent upon the initial health of the eye, as certain diseases of the retina can limit the final visual result. The ophthalmic surgeon will discuss this prior to any scheduling of surgery.
As with any surgery, there are risks associated with cataract surgery, and complications (such as bleeding, infection, corneal decompensation, macular swelling, and retinal detachment) can occur during or after surgery in spite of the best care. It is impossible to predict in which patients these complications will occur. Fortunately, the risk of these complications is quite low.