A cataract is a condition that many people develop as they get older.It makes the lens of the eye appear cloudy,making it more difficult for the patient to see.Doctors can remove cataracts through surgery.
Recently,a newly-built machine uses extremely small instruments to perform eye operations.The machine is reported to make fewer mistakes than doctors.Critics say cataract surgery is not very difficult,and the new machine may not be needed.But its inventor believes it shows that such small robotic devices could be used in many other ways.