NDA has very stringent medical norms, especially for eyes.

For pilot entry, you are debarred from all flying beaches, be it air force, army or navy.

Ground duty requires least limit of -2.5D, and you have -3.5D, so you might not make a cut in medicals of NDA as your eyesight is very weak for you to join NDA.

If you apply for TES entry in navy or army, they have a relaxation upto -3.5D.