Dear student,

The distance vision should be 6/6 in better eye and 6/9 in worse eye. Myopia should not be more than 2.5 D and hypermetropia should not be more than 3.5 D including Astigmatism.

Also the eyesight has different specifications as per the profession / field you are choosing. Hence it's better to read the guidelines which is given on official website of NDA as the eyesight specifications changes every year.