Hello This query is incomplete It's like "how many apples do I have if I have 5 oranges?" Power and visual acuity are two different things. You may have 6/9 vision and you may have even 6/60 vision with -0.5DS glasses depending on many factors like condition of retina etc

Hello Sir, Usually distant vision is corrected with the help of standard charts. If you have been prescribed a glass, your vision should improve upto 6/6 if everything else is normal. Here 6/6 means , you will be able to see clearly upto 6 meters with glasses what a normal person without glasses can see without glasses. Hope this explains helps solve your query.