I went to four different doctors for determining my eyeglass prescription. unfortunately the numbers are so different that i dont know which one i should use. what should i do? using some kind of average?

Unfortunately, the varying optometric prescriptions from office to office are far more commonly encountered than typically discussed. This was handled by my close companions by going to a Department of Ophthalmology at a local Medical School. Get a knowledgeable opinion, and make certain that eye dysfunction caused by diabetes for example is not playing a role.