When applying for a position with a covered employer, you may not be asked if you have a disability, but may be asked if you can perform the essential tasks or functions of the job. You are considered to be a qualified employee if you have the skills, experience and education for that position and can perform the essential functions of the job with or without an accommodation.
If you say you can perform the job but that you need an accommodation, then the employer must provide one or demonstrate that it would present an undue hardship. Also, your impairment need not last for a specific duration or be permanent; it can be as short as 6 months, so long as it substantially limits a major life activity when its symptoms are present.
Further, even if medication, hearing aids, medical devices or therapy can mitigate your disability, these are not to be considered in determining whether you meet the definition of being impaired under the ADA. The only exception to this is if wearing ordinary eyeglasses or contact lenses satisfactorily improves your vision.