My sister had sle disease and when it active doctor increase the dose of prednisolone 60 mg for 3 months she get cataract diseases can make operation?

Yes and yes. The use of any steroids can increase the risk for development of cataracts which will lead to blurry vision. Cataracts can be removed with surgery and vision can be restored.
Yes. Prednisone used chronically for diseases like sle may result in cataract progression that may sufficiently affect vision. Fortunately, cataract surgery can eliminate the cataract successfully in a high percentage of patients.
Steroid. Steroid (even though indicated) can also lead to cataracts. The cataracts may need surgery. But the alternative of not using the steroids may be more serious than having to take care of the cataracts.