Hello student!

As per your query I would like to inform you that if one of your eyesight is weak you can definitely give NDA but you won't be eligible to join Indian Airforce. In order to join Indian Airforce your vision for both the eyes should be 6/6. Since your eyesight is weak can go for Indian Army or Indian Navy provided your vision ranges from -2.5D to 3.5D.

You can also go for laser surgery to treat your eyesight and you are good to join any of the forces.

Hope it help!!