Validation is making sure that the user needs are met that consistently provides the intended medical benefits. Design validation checks if the input is equal to the user needs or the intended uses. Design verification proves that the medical device meets the user needs and intended use. Verification is to make sure that there is an objective evidence that specified requirements are met. Verification checks that if the input is equal to the output. I think design validation may not always needed since verification is enough since Verification is fine and there is no need to make any changes then validation is not required. Validation is meeting the needs of the device.