Hey,

NDA stands for National Defense Academy and it has certain standards which one needs to fulfil in order to be selected in it.

The eye power accepted is as follows,

For Myopia - a power of 3.5D and below is accepted

For Hypermetropia - should not be more that 3.5 D

As your power is 2.75 , so you are Eligible for NDA as per the standard set by them.

Hope that helps

Thank you.